Mr Rojas Says, "What Great Behavior Daniel Is Showing; He

Mr. Rojas says, "What great behavior Daniel is showing; he is standing quietly in line the way he is supposed to be." Soon, all of the third graders in Mr. Rojas's class are standing in line quietly like Daniel. In this example, what has happened to the class?

A) They are imitating Daniel because his behavior was reinforced.
B) The class received direct reinforcement.
C) The class received negative reinforcement.
D) The class received intermittent reinforcement.