Since the wildfires in southeastern Georgia sightings of black bears

Question

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Since the wildfires in southeastern Georgia, sightings of black bears, savannah cats, and bobcats in the urban areas near Savannah  have markedly increased, while the number of songbirds tallied by volunteer surveyors has declined.

A) have markedly increased, while the number of songbirds tallied by volunteer surveyors has declined

B) have markedly increased, while that of songbirds that are tallied by volunteer surveyors has declined

C) has markedly increased, while the number of songbirds that are tallied by volunteer surveyors has declined

D) has markedly increased, while songbirds tallied by volunteer surveyors have declined in number

E) increased markedly, while there was a decline in the number of songbirds tallied by volunteer surveyors

generis · Answer

Official Explanation:

Project SC Butler: Sentence Correction (SC2) 
 For SC butler Questions  Click Here

SHORT POE  
Choice A: Correct.

Choice B: No. The singular pronoun  that  does not agree with the plural noun  sightings . Pronoun agreement.

Choice C: No. The singular verb  has…increased  does not agree with the plural noun  sightings . Subject-Verb agreement.

Choice D: No. The singular verb  has…increased  does not agree with the plural noun  sightings . Subject-Verb agreement.

Choice E: No.  Sightings…increased markedly  is not parallel to  there was a decline in the number of songbirds . Parallel construction.

THE PROMPT

• Remove some of the fluff. 
→  Since the wildfires, sightings of black bears, savannah cats, and bobcats have markedly increased, while the number of songbirds tallied by surveyors has declined.

• Issue - THE number of / A number of
I have no idea why the writer of this question did not test the issue. I would have done so.
In any event, there are important differences between " the  number of Xs" and " a  number of Xs" that you must know.

1)  The  number of 
-- is always followed by a plural noun 
-- is always singular, even with that plural noun, because the phrase refers to an exact or specific quantity
Correct:  The number of books banned by the authoritarian right in the U.S. is increasing.

2)  A  number of 
-- is always followed by a plural noun
-- is always plural because the expression means "several"
Correct:  A number of factors underlie global warming, but the burning of fossil fuels is the biggest culprit.

I have inserted all of the answer choices into the prompt so that it is easier to see errors. 
The text from each answer choice is italicized.

THE OPTIONS  
 
• I do not see any errors

• Subject/verb agreement is correct 
→ The plural noun  sightings  agrees with the plural verb  have…increased.  
→ The singular noun  the number  agrees with the singular verb  has declined.  
KEEP

• Pronoun error
→ the singular pronoun  that  cannot be used to refer to plural  sightings .
→ the correct pronoun would be  those  
→ this pronoun usage is sometimes referred to as a "copy."
In this case,  those  would "make a copy" of the word  sightings,  which originally refers to bears and bobcats but in its "copy" form means "sightings  of songbirds ."
ELIMINATE B

• Subject/verb agreement
The plural subject sightings does not agree with the singular verb  has ... increased 
ELIMINATE C

• Subject/verb agreement
The plural subject sightings does not agree with the singular verb  has ... increased 
ELIMINATE D

• Not parallel
 Sightings have decreased  is not parallel to  there was a decline in the number of songbirds .
We must compare "apples to apples"—similar things.
It's also best to express these comparisons in parallel phrasing to advertise to the reader that a comparison is underway.

If you are not sure about parallelism, just compare option E to option A.
Which one is clearer?
In which option is it clearer that the sentence compares the prevalence of different kinds of animals?
In option E, is there any good reason to use "there was"?
Option A is the better answer.
Eliminate E.

The best answer is A.

Official Explanation:

This sentence is correct as written.

Because the underlined portion of the sentence contains the verbs  have…increased  and  has declined , check that they agree with their respective subjects.
The plural noun  sightings  agrees with the plural verb  have…increased.  
The singular noun  the number  agrees with the singular verb  has declined .

There appears to be no error in the original sentence, so keep choice A. 
Because there is no error in the original sentence, there are no obvious repeaters to look for, so evaluate the remaining answer choices individually, looking for reasons to eliminate each.

Choice B contains the same underlined verbs  have…increased  and  has declined  but it introduces an error with the use of the singular pronoun  that    to refer to the plural noun  sightings . 
This is a pronoun agreement error, so eliminate choice B.

Choice C incorrectly uses the singular verb  has…increased  to refer to the plural noun  sightings . 
This is a subject-verb agreement error, so eliminate choice C.

Choice D also incorrectly uses the singular verb  has…increased  to refer to the plural noun  sightings , which is a subject-verb agreement error. 
Eliminate choice D.

In choice E,  sightings…increased markedly  is not parallel to  there was a decline in the number of songbirds . 
This is a parallel construction error, so eliminate choice E.

The correct answer is choice A.

COMMENTS

Sushil117  , welcome to SC Butler.

These answers are excellent.
Well done, everyone.

zhanbo · Answer

My answer is  (A) . It took me 01:07.

(A) No obvious error. Keep for now. 
(B) No antecedent for "that" in "that of songbirds". 
The use of "tally" also strongly suggests that "number" be needed. 
(CD) Subject "sightings" does not agree with main verb ("has")
(E) "Since the wildfires" is a strong indicator that progressive tense should be used. 
In addition, "sightings ... increased" is not parallel wih "there was ... "

kungfury42 · Answer

I think the answer should be A.

(B) that tries to refer back to sightings but for it to do so correctly, it must be changed to "those"

(C) sightings has increased is a subject-verb disagreement

(D) sightings has increased is a subject-verb disagreement

(E) Incorrectly talks in past tense. When we are using since at the beginning of a sentence we would like to say that the effects of that event are still being witnessed.

Posted from my mobile device

winterschool · Answer

Since the wildfires in southeastern Georgia, sightings of black bears, savannah cats, and bobcats in the urban areas near Savannah have markedly increased, while the number of songbirds tallied by volunteer surveyors has declined.

A)  have markedly increased, while the number of songbirds tallied by volunteer surveyors has declined   Correct

B) have markedly increased, while that of songbirds that are tallied by volunteer surveyors  has  declined  Incorrect

C)  has  markedly increased, while the number of songbirds that are tallied by volunteer surveyors has declined  Incorrect

D)  has  markedly increased, while songbirds tallied by volunteer surveyors have declined in number  Incorrect

E)  increased markedly,  while  there was a decline  in the number of songbirds tallied by volunteer surveyors  Incorrect

Sightings is plural, has should be have. C & D out
E is in past form and has redundancy issues; Since present in sentence, so present form is correct
B has SV error - that of refers to Sightings, has should be have
Answer A

Sushil117 · Answer

"Sightings" is plural .so C & D are out right away due to SVA. should be "have" ,not "has"
in E ,sentence is in past tense. start with "since", indicates the action still not finished.so, should be in present tense .Incorrect
between A & B
A) have markedly increased, while the number of songbirds tallied by volunteer surveyors has declined
seems good. hang on

B) have markedly increased, while that of songbirds that are tallied by volunteer surveyors has declined
if "that of" is referring back to sightings, "has" should be "have" and "that of" should be "those of".SVA error

IMO A

generis · Answer

Click  here  to read the official explanation.

alex73195 · Answer

Since the wildfires in southeastern Georgia, sightings of black bears, savannah cats, and bobcats in the urban areas near Savannah have markedly increased, while the number of songbirds tallied by volunteer surveyors has declined.

A) have markedly increased, while the number of songbirds tallied by volunteer surveyors has declined

B) have markedly increased, while that of songbirds that are tallied by volunteer surveyors has declined

I was hesitated to pick A because the sentence doesnt have an apples to apples comparison. It compares sightings with a number of songbirds. Is this a valid concern?

Of course, B is also wrong because as mentioned in other posts, "that" should be "those".

ExpertsGlobal5 · Answer

Hello  alex73195 ,

We hope this finds you well.

To answer your query, Option A does not actually make a comparison; it simply states that the sightings of certain animals have increased, and simultaneously, the number of other types of animals has decreased.

We hope this helps.
All the best!
Experts' Global Team

VerbalBot · Answer

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Since the wildfires in southeastern Georgia sightings of black bears

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GMAT Sentence Correction (SC - EA only) Questions

Since the wildfires in southeastern Georgia sightings of black bears

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