遇到错题怎么办

OG 11th math P59，第108题

if x and y are different prime numbers, each greater than 2. which of the following is true?

答案认为 x-y is an even interger是对的。

但x都不一定大于y，这句话就应该是错的了。

万一考试遇到，我该选啥？