The volume of traffic at a certain intersection can be modeled by a periodic function. Traffic is at its lowest at midnight and noon with approximately 5 cars traveling through the intersection during a green light. Traffic peaks at 75 cars per green light during rush hour, which occurs twice a day at 6 am and 6 pm. Which one is incorrect?

A. The midline of the periodic function is y = 35

B. The period of the function is 12 hours

C. At 3 am there are an average of 40 cars traveling through the intersection during a green light.