What, in Relation to Other Personal Relationships, Is Unique About

What, in relation to other personal relationships, is unique about friendships?

A) Adult friends typically spend little time together.
B) Friendships are rarely emotionally intimate.
C) Friendships tend to be less egalitarian than romantic or work relationships.
D) The ending of a friendship is often gradual and tends not to be formally recognized.
E) all of the above