Here are the errors associated with a particular forecast over the past five months, in chronological order: 2 , 5 , 0 , 5 , 10 . Which of the following statements is (are) true? I. The forecast was too high during the fifth month. II. The mean error over these five months is 2 III. The forecast was perfectly accurate during one of the months. a. III only b. I and III c. I only d. I, II and III e. Il only.