When an ______ Is Presented the Probability of a Response

Multiple Choice

When an ______ is presented the probability of a response increases. When an _____ is presented the probability of response decreases.

A) S^D; S^∆
B) S^∆; S^D
C) S^D followed by a S^∆; S^∆ followed by a S^D
D) S^∆ followed by a S^D; S^D followed by a S^∆