Sufficient vs necessary

I got the correct answer, but I don't see how it could be *sufficient* to, by itself, guaranty the the conclusion. However, I do see why it's *necessary* for the conclusion; it just seems like it needs to be combined with the other premise (in the passage) to arrive at the conclusion. How is the correct answer a super premise? If someone tells me that "The greatest works of art are works that inevitably satisfy all critics," how can I -just from that- conclude that "most art criticism is devoted to works other than the greatest works of art"? I would also need to know the other premise (that "most art criticism is devoted to art works that fail to satisfy the critic") in order to conclude that.