Answer: Spontaneous recovery.
Explanation: Spontaneous recovery is stern used in Psychology to describe the sudden reappearance of a conditioned response after of it has been extinguished after a certain period of time.
ACCORDING TO PAVLOV A CLASSICAL PSYCHOLIGIST, THE SUDDEN REAPPEARANCE OF AN EXTINGUISHED CONDITIONED RESPONSE OCCURS AFTER A PERIOD OF NOT BEING EXPOSED TO THE CONDITIONED STIMULUS.