An important distinction between classical and operant conditioning is that:

a. classical conditioning involves voluntary responding, while operant conditioning involves involuntary responding.
b. classical conditioning involves reinforcement, while operant conditioning involves punishment.
c. classical conditioning involves cognitive learning, while operant conditioning involves associative learning.
d. responding does not affect the presentation of stimuli in classical conditioning, but in operant conditioning responding has consequences.

Answer: D

Rationale: In contrast to classical conditioning, which typically involves reflexive responses, operant conditioning involves voluntary actions such as speaking or listening, starting and stopping an activity, and moving toward or away from something.