Step 1: Read the sentence carefully.
The sentence is: "Although it does contain some path breaking ideas, one would hardly characterize the work as __________." We must pick two words from the list that can each fill the blank without changing what the sentence means overall.
Step 2: Understand what "hardly characterize" means.
"Hardly characterize the work as X" means the work is almost never described as X, in other words, the work is not really X. So whichever word goes in the blank, the sentence is saying this work is not truly X, even though it has some path breaking ideas.
Step 3: Check which pair keeps the sentence meaning the same either way.
For two words to be interchangeable here without changing the overall meaning of the sentence, they must be close synonyms of each other, so that saying "hardly X" and "hardly Y" amounts to saying the same thing about the work.
Look at the list: I. revolutionary, II. original, III. conventional, IV. interesting, V. innovative.
"Original" and "innovative" both describe something new, fresh, and not copied from existing ideas. If we say the work is "hardly original" or "hardly innovative," both sentences carry the same message: despite some path breaking ideas, the work overall does not feel new or groundbreaking.
"Revolutionary" is a stronger, more extreme word than either of these, so pairing it with "original" (option a) shifts the degree of meaning rather than keeping it steady. "Conventional" (option d, paired with interesting) is actually the opposite sense, calling the work ordinary rather than lacking originality, so it does not pair cleanly with "interesting" to preserve one steady meaning. "Interesting" (option b, paired with original) is a general word about being engaging, not about being new, so swapping it with "original" would change what the sentence is claiming.
Step 4: Final Answer.
"Original" and "innovative" are close synonyms, so filling either into the blank keeps the sentence's meaning steady. The correct option is (c), II and V.