Correct Answer: A
Explanation:
The very first word of the sentence, although, signals that the sentence is setting up a contrast between the critics and the curator. The critics had one opinions, but the curator had a different one. Since the curator liked the artworks well enough to acquire them, you can anticipate that the critics disliked the artworks. So the blank requires a word with negative connotations, and choice (S), insignificant, is the only one that works.
| Retroactive: | having application to or effect on things prior to its enactment |