The idiom has 2 forms : 1. So X as to Y. X = adjective, Y = verb. [the weather was so hot as to threaten the crops in the field. 2. So X that Y. X = adjective i think C is a bit too wordy, it would be correct if it said "so debilitating as to become an economic" If A was something totally weird, C can still work as the correct answer. But since A has the correct idiom and is concise, you got to pick that. Hard question i say ! |