Is the Set of Ordered Pairs a Function? for Each

Multiple Choice

Is the set of ordered pairs a function? For each function, name the set of inputs (domain) and the set of outputs (range) . (Dou, Ron) , (Dou, Ian) , (Dou, Vernon)

A) Function. Domain is {Dou}, range is {Ron, Ian, Vernon}.
B) Function. Domain is {Dou}, range is {Ron}.
C) Function. Domain is {Dou}, range is {Ron, Ian}.
D) Function. Domain is {Ron, Ian, Vernon}, range is {Dou}.
E) Not a function