Answer:
D) irony
Step-by-step explanation:
Irony refers to a rhetorical device in which what appears to be the case differs radically from what is actually the case. The device relies on the contrast between what is expected and what actually happens. In this case, Wilde claims that an age group is particularly knowledgeable. We would tend to assume that the age group he refers to is old people, as we generally assume that knowledge comes with experience. Instead, Wilde tells us that it is young people who know everything. Because the statement is unexpected, it can be considered an example of irony.