Although the researchers agreed unanimously on their expectations for the outcome of the experiment, their surprise was evident when the actual data started coming in.
A) their surprise was evident when
B) they were evidently surprised when
C) their surprise was in evidence when
D) they were evidently surprised as
E) they were surprised as
First of all, GMAT hates their and prefer they. We need to use their if there is no other correct answer.
a). Passive voice, Keep it aside and if you can find any active voice in other answer then remove it.
c) Meaning changed and awkward
E) It removed adverb all thogher.
Now with remaining B and D.
B.they were evidently surprised when the actual data started coming in.They were surprised when they saw data strarting coming in. It is referring a point of time.
D.they were evidently surprised as the actual data started coming in.This refer that Scientist were surprised for the long time till data was coming in. Or in other words they are continuously in surprised status. OR another use of as suggest that scientist were evidently surprised in same manner as "the actual data started coming in". so its ambugious and wrong choice.
I hope my explanation helps.
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