We didn't believe in his statement, but subsequent events proved that he was right.

The correct answer is A. later.

The statement "We didn't believe in his statement, but subsequent events proved that he was right" means that we did not believe what he said at the time, but later events showed that he was correct. This is consistent with the definition of the word "subsequent," which means "happening or coming after something else."

The other options are not correct because they do not match the meaning of the statement. The word "earlier" would mean that we believed him at the time, but later events showed that he was wrong. The word "many" would mean that there were many events that proved him right, but the statement does not say anything about the number of events. The word "few" would mean that there were only a few events that proved him right, but the statement does not say anything about the number of events.