Jamene hit her head approximately every thirty seconds. It is hypothesized that her behavior is maintained by parental attention, her strongest reinforcer. Jamene has a limited repertoire, such that the behavior analyst observed no other relevant behavior. It is important that the behavior analyst tries to decrease head hitting as soon as possible, as Jamene is starting to bruise. What would be the best differential reinforcement procedure to initially and temporarily use? 1) DRH 2) DRO 3) DRA 4) DRI