Which of the following is a difference between variable interval reinforcement schedules and variable ratio reinforcement schedules? a. Variable interval reinforcement schedules are intermittent reinforcement schedules that are based on time, whereas variable ratio reinforcement schedules are intermittent reinforcement schedules that are based on behaviors. b. Unlike variable interval reinforcement schedules, with variable ratio reinforcement schedules, consequences follow a behavior only after a fixed time has elapsed. c. Variable interval reinforcement schedules are a type of continuous reinforcement schedules, whereas variable ratio reinforcement schedules are a type of intermittent reinforcement schedules. d. Unlike variable interval reinforcement schedules, with variable ratio reinforcement schedules, consequences are delivered following a specific number of behaviors.