I think its C

As it's talking about a range of volcanoes and also the action has incurred in the past so "were" should be the right one

IMO B

Here is my Reasoning -
Subject is - A range of volcanoes - and collectives are singular hence we would want a singular verb and since this we are taking about something in the past we will prefer was
Hence eliminate - C & D
No need for "Have Been" so E is gone
A v B
A says definitely this thing led to the demise of dinosaurs - however factually we still don't know what led to it hence in B "that could have led" wins the race.

So excited for the Next 12 days:

Near the end of the Cretaceous period, a range of volcanoes in western India called the Deccan Traps was thought to be the site of several climate-altering eruptions that led to many extinctions, including the demise of the dinosaurs.

(A) was thought to be the site of several climate-altering eruptions that led - Correct answer

(B) was thought to be the site of several climate-altering eruptions that could have led - could have hints to speculation, but the tone is of the author does not seem to be so.

(C) were thought to have been the site of several climate-altering eruptions that led - SV error, the subject is " a range of.." - singular

(D) is thought to have been the site of several climate-altering eruptions that led - have been is wrong. As Extinctions occurred in the past

(E) was thought to have been the site of several climate-altering eruptions that led - have been is wrong. As Extinctions occurred in the past
_________________

Answer: B

Near the end of the Cretaceous period, a range of volcanoes in western India called the Deccan Traps was thought to be the site of several climate-altering eruptions that led to many extinctions, including the demise of the dinosaurs.

(A) was thought to be the site of several climate-altering eruptions that led
(B) was thought to be the site of several climate-altering eruptions that could have led
(C) were thought to have been the site of several climate-altering eruptions that led
(D) is thought to have been the site of several climate-altering eruptions that led
(E) was thought to have been the site of several climate-altering eruptions that led

Explanation: We are modifying 'a range' so the verb should be singular. Also, the event occurred in the past so the verb should be in the past tense i.e. 'was'.

Option A: Was thought is correct though we are not sure whether these volcanoes were actually the cause of the demise of dinosaurs. Hence A is incorrect as it implies that Volcanoes caused the demise of dinosaurs.

Option B: B is correct - singular and past tense of the verb - was. Also, it implies that the volcanoes could have led to the demise which is exactly what was thought to be.

Option C: Were is incorrect as discussed above.

Option D: Is is incorrect as discussed above.

Option E: 'Was thought to have been' signifies a very different meaning. The site was not thought to have been - the fact that it led to the demise of the dinosaur was thought to have been.

"Near the end of the Cretaceous period" - Past Tense is needed (D is out)
"a range of volcanoes" - singular verb (C is out)
"was thought to be the site of several climate-altering eruptions that could have led" - B
"was thought to have been the site of several climate-altering eruptions that led" - E

Option E.

Since the phrase in question should be in the impersonal passive voice, "to have been" is the correct phrase as opposed to "to be" which eliminates A and B. Option C is wrong because "a range" is singular and "were" does not agree with the subject, and Option D is wrong because "is" is in the present tense. So E is the only one remaining, which is correct.

Near the end of the Cretaceous period, a range of volcanoes in western India called the Deccan Traps was thought to be the site of several climate-altering eruptions that led to many extinctions, including the demise of the dinosaurs.

First, look at the core of the sentence:
a range of volcanoes in western India called the Deccan Traps was thought to be the site of several climate-altering eruptions
that led to many extinctions

Pre-think - Errors:
. a range ... was thought to be the site of ... eruptions that led ...
--> "to be" doesn't sound right. We should use "to have been" because the action "be" was completed in the past.

(A) was thought to be the site of several climate-altering eruptions that led

(B) was thought to be the site of several climate-altering eruptions that could have led
Redundant --> We simply need "that led" because we already have "was thought" which describes the belief.

(C) were thought to have been the site of several climate-altering eruptions that led
Singular subject a range requires a singular verb was

(D) is thought to have been the site of several climate-altering eruptions that led
The belief no longer exists --> We should use was

(E) was thought to have been the site of several climate-altering eruptions that led
Correct answer: E

“a range of” makes the sentence singular, we need a singular verb then. Because of “thought” we should use a conditional.
a) Missing conditional
b) Correct
c) Plural “were” does not agree in number with “a range of volcanoes”. Were thought to “have been” is not the correct tense.
d) Present tense “is” is incorrect.
e) “was thought to have been” is not the correct tense.

The first underlined word is modifying 'a range of' which is a collective noun, the modifier has to be singular, so C is out.

The action occurred in the past and also going by the meaning it seems the author is saying it WAS believed so not necessarily it IS still the case. St. B, D and E unnecessarily introduce present perfect when the action took place in the past and is done(completed).
A simple 'had led' can work , so B D E are out.

Answer A.

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Near the end of the Cretaceous period, a range of volcanoes in western India called the Deccan Traps was thought to be the site of several climate-altering eruptions that led to many extinctions, including the demise of the dinosaurs.

a range of volcanoes => singular C and E out
was thought and could have led => i think both are about probability so could have led is unnecessary B out
is thought to have been => the incident was in the past and it ended so i believe wrong tense. D out

Answer is A

Poe: was vs were: a range --> was.
A,B,E remaining
E. Have been. Continuous. Out.
Between A & B.
B. could have led to - not required.

A remaining.

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Near the end of the Cretaceous period, a range of volcanoes in western India called the Deccan Traps was thought to be the site of several climate-altering eruptions that led to many extinctions, including the demise of the dinosaurs.

(A) was thought to be the site of several climate-altering eruptions that led
(B) was thought to be the site of several climate-altering eruptions that could have led
(C) were thought to have been the site of several climate-altering eruptions that led
(D) is thought to have been the site of several climate-altering eruptions that led
(E) was thought to have been the site of several climate-altering eruptions that led


Deccan Traps is the name of range of volcanoes so we would consider it as singular entity, so (C) is out.
We are talking about an event in the past which has no relation with the present(Near the end of the Cretaceous period was the site in the past which later led to extinctions). (D) is out.
Use of 'have been' means it is still going on which is not the case. (E) is out.

Since, a thought is being expressed, use of 'could have' fits the sentence.
Correct option - (B)

Near the end of the Cretaceous period,
a range of volcanoes in western India called the Deccan Traps was thought to be the site of several climate-altering eruptions that led to many extinctions, including the demise of the dinosaurs.
--No errors

(A) was thought to be the site of several climate-altering eruptions that led
--correct
(B) was thought to be the site of several climate-altering eruptions that could have led
-- the expression-'could have led' is redundant as we are expressing the same function by saying 'it was thought to be'.

(C) were thought to have been the site of several climate-altering eruptions that led
-- S-V agreement error.[were is incorrect for a range of volcanoes]
(D) is thought to have been the site of several climate-altering eruptions that led
-- use of present tense is incorrect.(we are talking about past event)
(E) was thought to have been the site of several climate-altering eruptions that led
-- usage of 'have been' is incorrect as it indicates it is still considered as a site if climate altering eruptions.

IMO A

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[quote="Bunuel"]12 Days of Christmas GMAT Competition with Lots of Fun

Near the end of the Cretaceous period, a range of volcanoes in western India called the Deccan Traps was thought to be the site of several climate-altering eruptions that led to many extinctions, including the demise of the dinosaurs.

(A) was thought to be the site of several climate-altering eruptions that led
(B) was thought to be the site of several climate-altering eruptions that could have led
(C) were thought to have been the site of several climate-altering eruptions that led
(D) is thought to have been the site of several climate-altering eruptions that led
(E) was thought to have been the site of several climate-altering eruptions that led




Deccan Traps is the name of range of volcanoes so we would consider it as singular entity, so (C) is out.
We are talking about an event in the past which has no relation with the present(Near the end of the Cretaceous period was the site in the past which later led to extinctions). (D) is out.
Use of 'have been' means it is still going on which is not the case. (E) is out.

Since, a thought is being expressed, use of 'could have' fits the sentence.
Correct option - (B)

Near the end of the Cretaceous period, a range of volcanoes in western India called the Deccan Traps was thought to be the site of several climate-altering eruptions that led to many extinctions, including the demise of the dinosaurs.

(A) was thought to be the site of several climate-altering eruptions that led Correct

(B) was thought to be the site of several climate-altering eruptions that could have led Incorrect

could have led - uses wrong, action already happened

(C) were thought to have been the site of several climate-altering eruptions that led Incorrect

SV error - were uses wrong, a range is singular
Tense error - thought to have been uses wrong, it can be change in future

(D) is thought to have been the site of several climate-altering eruptions that led Incorrect

Tense error - thought to have been uses wrong, it can be change in future
is uses wrong, a range of volcanoes was a site in Cretaceous period

(E) was thought to have been the site of several climate-altering eruptions that led Incorrect

Tense error - thought to have been uses wrong, it can be change in future

Near the end of the Cretaceous period, a range of volcanoes in western India called the Deccan Traps was thought to be the site of several climate-altering eruptions that led to many extinctions, including the demise of the dinosaurs.

(A) was thought to be the site of several climate-altering eruptions that led
Correct

(B) was thought to be the site of several climate-altering eruptions that could have led
Incorrect: Since leading to extinction is a fact, "could have led" shows uncertainty. Hence it is incorrect.

(C) were thought to have been the site of several climate-altering eruptions that led
Incorrect: "Were" is a plural verb for a singular subject "Range"

(D) is thought to have been the site of several climate-altering eruptions that led
Incorrect: "Is" is in present tense but the verb should be in past.

(E) was thought to have been the site of several climate-altering eruptions that led
Incorrect: "Was thought to have been" is incorrect

The correct answer is B.

The singular verb 'was' agrees in number with the singular subject 'range of volcanoes'.
'would' is used correctly as it is an assumption.

Near the end of the Cretaceous period, a range of volcanoes in western India called the Deccan Traps was thought to be the site of several climate-altering eruptions that led to many extinctions, including the demise of the dinosaurs.

(A) was thought to be the site of several climate-altering eruptions that led
(B) was thought to be the site of several climate-altering eruptions that could have led
(C) were thought to have been the site of several climate-altering eruptions that led
(D) is thought to have been the site of several climate-altering eruptions that led
(E) was thought to have been the site of several climate-altering eruptions that led


Here if we look at the pivots, we will see a clear distinction between was and is and also was and were. But since 'a range of volcanoes' is singular, 'was' is more appropriate.This cancels out C. Also present tense is wrong, since it talks about a past event. D out. E and b is too wordy.

Hence A is the correct answer.

Answer is A.
Range is singular, so was will be considered.
Furthermore, one can eliminate B because it shows possibility not a sure shot thing. The sentence seems to be conveying a sure thing.
E can be eliminated because it uses perfect tense again signifying that site ceased after the end of the period

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