Calvin Refuses to Eat His Spinach

Multiple Choice

Calvin refuses to eat his spinach.His father asks,"Calvin,do you want to grow up to be big and strong?" Calvin says,"Yes." The father says,"Popeye eats spinach and he's strong,don't you agree Calvin?" Calvin again says,"Yes." The father then says,"Then why don't you eat your spinach?" What influence tool is the father using? 

A)  commitment and consistency 
B)  social proof 
C)  reciprocation 
D)  liking 
E)  authority