Answer:
Classical conditioning involves an association between two stimuli and whereas operant conditioning requires behavior on the part of the learner.
Explanation
Because of this, classical conditioning can imposed without reward or punishment. When we pair a neutral stimuli with a conditioned stimuli, over the time people will start to give conditioned response for the neutral stimuli.
Operant conditioning on the other hand, require a certain type of reward or punishment that has to be given based on whether the subject is conducting a desired behavior or not.