Mr Smart Tells His Students That They Can Do Whatever

Multiple Choice

Mr. Smart tells his students that they can do whatever they want for the first ten minutes of class but must then turn their attention to the day's assignment. The students are delighted with their ten minutes of free time but they don't attend to the assignment when it's time to do so. From an operant conditioning perspective, what mistake has Mr. Smart made?

A) There is a delay in reinforcement.
B) He has used negative reinforcement instead of positive reinforcement.
C) Free time is not an effective reinforcer for the students.
D) The "reinforcer" is presented before the response.