Molly is potty training her daughter, Mia. Every time Mia begins to urinate in her diaper, Molly says the word "bathroom" in the hope that Mia will begin to urinate when she hears this word while sitting on the toilet. Molly's efforts most resemble the studies of:
A) B. F. Skinner, who studied operant conditioning
B) Edward Tolman, who studied latent learning
C) Sigmund Freud, who studied psychodynamic effect
D) Ivan Pavlov, who studied classical conditioning
E) Stanley Milgram, who studied obedience

D) Ivan Pavlov, who studied classical conditioning  

Explanation:

Classical conditioning: In psychology, the term classical conditioning is determined as a learning theory which was proposed by Ivan Pavlov. In classical conditioning theory, a "conditioned stimulus" or CS tends to get connected with an unrelated or unlearned "unconditioned stimulus" or UCS to give rise to a "behavioral response" referred as a "conditioned response"  or CR (learned response of formerly neutral stimulus).

In the question above, Molly's efforts most resemble the studies of "Ivan Pavlov, who studied classical conditioning".