Mr Woodward Takes an Antihistamine and Reports That It Also

Mr. Woodward takes an antihistamine and reports that it also has a mild, calming effect on him. His physician tells him that this is not at all unusual. The antianxiety effect of this drug is called a(n) :

A) adverse effect.
B) side effect.
C) therapeutic effect.
D) allergic reaction.
E) none of the above.