Alec Wants to Train His Dog Magnus to Sit on Command

Alec wants to train his dog Magnus to sit on command. To achieve this goal, Alec starts by giving Magnus a strip of bacon and saying "sit" every time Magnus sits. A day later, Alec gives Magnus a strip of bacon and a pat on the head and says "sit" every time Magnus sits. Magnus seems to learn to sit on command. However, after a few days of training, Alec notices that Magnus now salivates and wags his tail whenever he hears the word "sit."
-Over the following days,Alec noticed that Magnus would salivate and wag his tail whenever he heard Alec say the word "fit".What is this known as

A) stimulus discrimination
B) stimulus generalization
C) an unconditioned response
D) a fixed action pattern