Two different versions of Gmatprep Mary Leakey SC

The following two questions are from GMATPREP. They are slightly different but I don't think the difference is drastic. However, the OA for the questions are totally different (see below). Can someone explain the difference between these two problems that cause them to have different answers? How did you get the correct answer for each one? I am so confused...please help.

In addition to her work on the Miocene hominid fossil record, Mary Leakey contributed to archaeology through her discovery of the earliest direct evidence of hominid activity and through her painstaking documentation of East African cave paintings.
A. Mary Leakey contributed to archaeology through her discovery of the earliest direct evidence of hominid activity and through her painstaking documentation of
B. Mary Leakey contributed to archaeology by her discovery of the earliest direct evidence of hominid activity and painstakingly documenting
C. Mary Leakey was a contributor to archaeology by discovering the earliest direct evidence of hominid activity and with her painstaking documentation of
D. Mary Leakey's contributions to archaeology include her discovery of the earliest direct evidence of hominid activity and painstakingly documenting
E. Mary Leakey's contributions to archaeology include her discovering the earliest direct evidence of hominid activity and painstaking documentation of


In addition to her work on the Miocene hominid fossil record, Mary Leakey contributed to archaeology with her discovery of the earliest direct evidence of hominid activity and painstakingly documenting East African cave paintings.
A. Leakey contributed to archaeology with her discovery of the earliest direct evidence of hominid activity and painstakingly documenting
B. Leakey contributed to archaeology by her discovery of the earliest direct evidence of hominid activity and by painstakingly documenting
C. Leakey was a contributor to archaeology with her discovery of the earliest direct evidence of hominid activity and with her painstaking documentation of
D. Leakey’s contributions to archaeology include her discovery of the earliest direct evidence of hominid activity and her painstaking documentation of
E. Leakey’s contributions to archaeology include her discovering the earliest direct evidence of hominid activity and painstaking documentation of




Question No:1
This is a case of misplaced modifiers..Here IN ADDITION TO HER WORK should be followed by the person to whom it is referring to and so the other part of the sentence would be begin with MARY LEAKEY and not MARY LEAKEY'S CONTRINUTIONS..that leaves us with A,B and C..


Now its a matter of PARALLEL CONSTRUCTION..DISCOVERY is parallel to DOCUMENTATION..Hence A is the answer.

If you watch closely, its the same case with Question 2

Thank you for your reply!
The OA for #1 is A which means the beginning phrase modifies "Mary Leakey". But the OA for #2 is D which means the beginning phrase modifies "Mary Leakey's contributions". How can the phrase correctly modify both subjects and still be correct? To me, "Mary Leakey's contributions" as a subject makes more sense. Please explain...

Same here..i choose E for the 1st and D for the 2nd..."In addition to her work"..doesnt that mean Mary Leakey's work i.e Marry Leakey's contribution..

How A can be the OA for 1st??
can anyone pls explain..

opening this unexplained thread again , can n e one explain the difference....

experts pls comments

source Gmat prep

Final solution at one place:

Important: The purpose of this post (and all the other posts by me) is to give a complete solution to all GMAT-Prep Verbal questions at one place. Sometimes students have to wade through dozens of posts to get to the final answer. My posts will give one complete and crisp solution required to arrive at the correct answer by eliminating the wrong one. Some of the content in these posts may have been taken from various other sources (discussion forums).

In addition to her work on the Miocene hominid fossil record, Mary Leakey contributed to archaeology with her discovery of the earliest direct evidence of hominid activity and painstakingly documenting East African cave paintings.
(A) Leakey contributed to archaeology with her discovery of the earliest direct evidence of hominid activity and painstakingly documenting
(B) Leakey contributed to archaeology by her discovery of the earliest direct evidence of hominid activity and by painstakingly documenting
(C) Leakey was a contributor to archaeology with her discovery of the earliest direct evidence of hominid activity and with her painstaking documentation of
(D) Leakey's contributions to archaeology include her discovery of the earliest direct evidence of hominid activity and her painstaking documentation of
(E) Leakey's contributions to archaeology include her discovering the earliest direct evidence of hominid activity and painstaking documentation of

A, B: ‘discovery’ is not parallel to ‘documenting’
E: ‘discovering’ is not parallel to ‘documentation’
C: uses the wrong idiom ‘was a contributor with’ … completely wrong.

D is correct.

Another version of the same question:

In addition to her work on the Miocene hominid fossil record, Mary Leakey contributed to archaeology through her discovery of the earliest direct evidence of hominid activity and through her painstaking documentation of East African cave paintings.
A. Mary Leakey contributed to archaeology through her discovery of the earliest direct evidence of hominid activity and through her painstaking documentation of
B. Mary Leakey contributed to archaeology by her discovery of the earliest direct evidence of hominid activity and painstakingly documenting
C. Mary Leakey was a contributor to archaeology by discovering the earliest direct evidence of hominid activity and with her painstaking documentation of
D. Mary Leakey's contributions to archaeology include her discovery of the earliest direct evidence of hominid activity and painstakingly documenting
E. Mary Leakey's contributions to archaeology include her discovering the earliest direct evidence of hominid activity and painstaking documentation of

B, D: ‘discovery’ is not parallel to ‘documenting’
C, E: ‘discovering’ is not parallel to ‘documentation’

A is correct.