Of the Following Situations, Which Would Be an Example of Authority

Of the following situations, which would be an example of authority?

A) A person insisting that his or her friend attend a particular movie
B) A teacher requiring a research paper in his or her class
C) You telling your little brother that he cannot stay up to watch a movie with you because it's past his bedtime
D) A playground bully making a person get off the swings
E) A mugger who shoves a gun in a person's back and demands his or her money