It was the coincidence of the geographic range of the sickle cell gene

In the example you stated, two points of time are described that coincided : 1. The time when Einstein researched. 2. the time when Max Plank researched.
Both these points of time COINCIDED. Because of the very meaning of the word "coincidence", there must be at least two events / entities that should occur together (same place OR same time). The word coincide is not applicable for a single event or entity.

At this question we need to focus on the difference between coincidence and coinciding with ... the word coinciding means --> 2 things happening at the same time. Hence the meaning changes in the options that include the "coinciding" ... The meaning of the sentence is the coincidence of the geographic ranges of the sickle cell gene and malaria ... not the geographic range. Always the first sentence provides the fundamental meaning of the sentence that we should focus on.

Cheers!

It was + noun + that is the correct structure in SC; this structure does not usually appear in SC questions. Gmatclub test also has one question of this structure.
E also uses "it was" but E is surely wrong.
"coinciding with malaria that " violates parallel structure.
C and D are awkward.

I think if the sentence would have been like given below,then it would have been correct. I still find A wrong:

It was the coincidence of the geographic range of the sickle cell gene and that of malaria which

Lets see if I can explain this one!
sickle cell and malaria are parallel, as marked by the "and" in between.This means that we can take words that need to appear in both as common.
So, we can see now that "geographic range of the" is common.
If you see it in that form, option A looks correct.
Additionally, in D, "ranges" is plural and "was" is singular. In E, what does the first "that" refers to?
In C, "and" is missing, so it is saying, geographic range coincided with malaria.B is active voice of C and has the same error as "C".
So, using Process of Elimination, we come to the same conclusion.

There seems to be a lot of disagreement on this question, particularly the correct option, i.e. option A, which seems to have an illogical comparison. Plus it is marked as an official GMAT Paper Test question.

Could you please explain why is option D wrong.
In one of the responses, someone said the 'was' is wrong in option D but dont think so. I believe the whole phrase ''the geographic ranges of A & B'' is acting as a noun phrase for which a singular verb - was - is correct

(D) The geographic ranges of the sickle cell gene and malaria coinciding was what SV Error

(E) It was that the geographic ranges of the sickle cell gene and malaria were coincident that S error

Both D & E can easily be eliminated.

Final battle is among A, B & C

(A) It was the coincidence of the geographic range of the sickle cell gene and malaria that

(B) It was the geographic range of the sickle cell gene coinciding with malaria that Meaning error

(C) The geographic range of the sickle cell gene coinciding with malaria was what Meaning error

It's not the range that drew attention, It's the coincidence of the range.. We need to apply meaning here as there are no known errors.


IMO A(1:30)

It was the coincidence of the geographic range of the sickle cell gene and malaria that first drew attention to the possibility that the sickle cell gene might confer resistance to the disease.

Option Elimination -

(A) It was the coincidence of the geographic range of the sickle cell gene and malaria that - Not ideal but best of the worst lot. "that" refers back to the coincidence. The first "that" introduces a relative clause, a noun modifier. A noun modifier can jump over a prepositional phrase except the verb.

(B) It was the geographic range of the sickle cell gene coinciding with malaria that - "coinciding" followed by the gene. ING modifier without comma modifies the nearest noun. Sickle cell gene coinciding with Malaria? No. The coincidence was in terms of their geographic ranges.

(C) The geographic range of the sickle cell gene coinciding with malaria was what - same issue.

(D) The geographic ranges of the sickle cell gene and malaria coinciding was what - The geographic ranges (plural subject) and singular verb (was). SV issues.

(E) It was that the geographic ranges of the sickle cell gene and malaria were coincident that - This is a total mess up. "It was that." What is the purpose? "that" here is acting as a connector and not a relative pronoun. When used like this to introduce a subordinate clause, it adds more information to what happened before it. E.g., I believe that she is coming. Here, "that she is coming" adds more information to the author's belief. But in our sentence, can we say "that the geographic ranges of the sickle cell gene and malaria were coincident" to add more info about "it was"? No. Moreover, the second that is referring to what? Coincident? That is an adjective and not a noun. Coincidence is a noun. This double "that" construction is a bit inferior in this case.