OE


C, E The blank is at the end of the sentence, but the main clue comes toward the beginning; "conflicting" indicates a contrast between the results of the studies. The sentence describes "unpleasant results," so the missing word must describe results that contrast with this. You are looking for a pair of synonyms that have a positive tone and mean something like "pleasant" or "healthy." (C) salubrious means "healthful," and (E) beneficent means "advantageous," so that's the correct pair. (A) addictive may catch your eye because caffeine can in fact be habit-forming, but the missing word refers to its positive properties. (B) lackadaisical means "without enthusiasm," which doesn't fit the context. (D) adventitious may be tempting as it looks similar to "advantageous," but it actually means "extrinsic" or "not inherent." Finally, (F) innocuous, or "harmless," is not strong enough to contrast with "unpleasant;" furthermore, no other word gives the sentence a similar meaning.