Final answer:
A multiple schedule involves two or more simple schedules presented sequentially and signaled by an arbitrary stimulus.
Step-by-step explanation:
The correct answer is A) Multiple schedule.
A multiple schedule involves two or more simple schedules presented sequentially and signaled by an arbitrary stimulus. Each schedule has its own discriminative stimulus and the organism is required to emit a different response for each schedule in order to obtain reinforcement.
An example of a multiple schedule is when a rat is placed in an experimental chamber where it has to press a lever to obtain food during one schedule and climb a ladder to obtain water during another schedule.