What is spontaneous recovery?

A) a learned decrease in responding
B) an increase in responding after a delay following extinction
C) a response to a stimulus that resembles the stimulus used in training
D) a conditioned response to a stimulus that followed the unconditioned stimulus

Spontaneous recovery is the reappearance of a previously extinguished conditioned response after a delay. In other words, the organism exhibits an increase in responding to the conditioned stimulus after a period in which it was not presented. Option A refers to extinction, option C refers to stimulus generalization, and option D refers to classical conditioning.