In Mr. Marshall's classroom, students who acquire 20 points in one day can have a half hour of free time at the end of the day. Mr. Marshall awards points to his students for good behavior and deducts points when they misbehave. The deduction of points for misbehavior is known as:_______
a. response cost.
b. in-school suspension.
c. a logical consequence.
d. time-out.