How is the interresponse time (IRT) calculated using a DRO schedule? a. The total time a DRO schedule is to be put into effect by the teacher is divided by the number of times the inappropriate behavior occurs within the established time interval. b. The number of times the behavior occurs is divided by the total time a DRO schedule is to be put in effect by the teacher. c. The number of times the behavior occurs is divided by the initial interval length a student must refrain from his or her inappropriate behavior to obtain reinforcement. d. The number of times the behavior occurs within the total time a DRO schedule is in effect represents the calculated interresponse time (IRT)