Question: What is the primary difference between fixed and variable reinforcement schedules? Question options: Need Assignment Help? a) Fixed schedules provide reinforcement unpredictably, while variable schedules are based on a set interval. b) Fixed schedules deliver reinforcement after a consistent number or time, while variable schedules occur unpredictably. c) Fixed schedules are only used for punishment, while variable schedules are used for reinforcement. d) Fixed schedules reinforce every behavior, while variable schedules reinforce none.