A clique is

A$.$ a social unit structured by unique values and standards of behavior, with leaders and followers

B$.$ a small group of about $3$ to $9$ members who are unusually alike demographically and who are good friends.

C$.$ a large, loosely organized peer group in which membership is based on reputation and stereotype.

D$.$ a strictly organized, hierarchical society in which members are tested in order to be admitted and punished severely for group$-$perceived violations of code.