Bunuel
The researcher, presenting his recent research that addressed the topic of dexterousness in nonhuman primates, demonstrated that he was challenging established opinion concerning captive animals,
comparing "termite-fishing" to nut-cracking, and he combed the published data on tool use in the wild.
(A) comparing "termite-fishing" to nut-cracking, and he combed
(B) comparing "termite-fishing" to nut-cracking, and combing
(C) was comparing "termite-fishing" to nut-cracking, while he combed
(D) he compared "termite-fishing" to nut-cracking and combed
(E) he was comparing "termite-fishing" to nut-cracking, and combing
Not 100% sure about this one, but in my opinion:
(A) comparing "termite-fishing" to nut-cracking, and
he combed--> This is not parallel: "...demonstrated that he was
challenging established opinion concerning captive animals,
comparing "termite-fishing" to nut-cracking, and
he combed the published data on tool use in the wild."
When he demonstrated that did he this 3 things (challenging, comparing and combing), then all 3 items should be in the same form (present participle in this case). But the 3rd item is not in that form.
I am unsure if the 2nd item is actually a modifier of the first item (challenged an opinion by comparing two techniques). But I that in this case, the 'that' should be repeated before the 3rd item IMO: "...
that he was challenging ... and
that he combed ..."
Is my way of thinking correct?
(B)
comparing "termite-fishing" to nut-cracking, and
combing--> Correct IMO: 3 participles in a parallel way (but check my concerns on Answer A)
(C)
was comparing "termite-fishing" to nut-cracking,
while he combed
--> This is not parallel. If the list would consist of only two items (challenging & comparing), then an 'and' is needed before the second item (and no comma). But this is not the case.
Furthermore, the "was" before the first item can count for the second item as well. Therefore, it is not necessary to repeat it. But I think that is not a reason to definitely cross out an answer.
(D)
he compared "termite-fishing" to nut-cracking and combed
--> not parallel: 'he' is repeated in the second item, but not in the third item
(E)
he was comparing "termite-fishing" to nut-cracking, and combing
--> not parallel: 'he was' is repeated in the second item, but not in the third item
Please share your thoughts on my solution.