Which Set of Events Below Would Be Most Likely to Elicit

Multiple Choice

Which set of events below would be most likely to elicit an adjunctive behavior while a rat is pressing a lever on a lean variable ratio schedule?

A) The presentation of a CS signaling food
B) The presentation of a CS that is inhibitory for food
C) The joint presentation of excitatory and inhibitory CSs for food
D) Increasing the rate of reinforcement