Read the scenario below and answer the question that follows.Susan is watching a football game when the game goes to commercial. She knows that each commercial break during the game takes a different amount of time to resolve. She gets up to make a snack for herself. She checks back frequently to see if the game is back from commercial. After 3 minutes and 30 seconds, the game comes back on and Susan returns to the room.Which of the following statements is true?A.Susan is on a fixed-interval schedule of reinforcement.B.Susan is on a variable-interval schedule of reinforcement.C.Susan is on a fixed-ratio schedule of reinforcement.D.Susan is on a variable-ratio schedule of reinforcement.