I was asked to choose, between two options, the correct. The question:
A pair of words formed with prefixes that convey the same meaning is
( x ) inside/intimate
( ✓ ) impossible/discourage
It's claimed that the answer was the second one because both "im" and "dis" hold similar contrary meaning. Nevertheless, at a first glance, I didn't even hesitate to choose the first option, because, unlike the second alternative, they have prefixes "in" and the word "intimate" is certainly related to something from "inside".
My confusion comes from the fact that the question structure is utterly ambiguous, since either "a pair of words" or the "prefixes" can convey the same meaning.
How can I properly argue, based on grammar or concrete references, that the ambiguity present in the question: A pair of words formed with prefixes that convey the same meaning confuses readers and makes two possible answers if there were?