Present Perfect - Present tense

Hi ronnie1985:
I agree with your comment that it makes sense for present tense to be used here as much as a past tense. However, I do agree with the OA, but not with the OE. I would reject D because it uses “may be” instead of “maybe”.

“Maybe” is an adverb which means the same as perhaps. “May be” is a verb phrase that means “could be”. So I rejected D, on basis of this alone. Now, if D said maybe, the sentence would be grammatically correct. In that case, if there were two options, I might pick E because it plays better with the following predicate (who pioneered the study of several new elements and paved the way for some of the great discoveries of the modern era) which is in past tense. However, that would be more a stylistic thing than sentence correction.

So, D here is wrong because it uses may be instead of maybe. Otherwise, grammatically, it would be correct. But stylistically, I would pick E.

Let me know if this helps

Present perfect is used to indicate that something has happened at an indeterminate time before the present moment. This makes sense for talking about the scientists who have won the Nobel Prize (since there is not an exact moment in the past when all of the prizes were won), but when speaking about Mendel, we must take care to match the past tense "pioneered" that is outside the underlined portion.