When Antonio Was Sick as a Child,his Mother Would Always

Multiple Choice

When Antonio was sick as a child,his mother would always make him vanilla pudding.To Antonio it seemed like the vanilla pudding made him feel better.Even now,he still gets a good feeling when he starts to prepare some vanilla pudding,but NOT when he starts to make any other type of pudding.What process does this illustrate

A)  stimulus generalization 
B)  instinctive drift 
C)  stimulus discrimination 
D)  negative avoidance