A shop is open 9 AM - 7 PM. The function r(t), graphed above, gives the rate at which customers arrive (in people/hour) at time t, where t measures time in hours since 9 AM. Suppose that the salespeople can serve customers at a rate of 75 people per hour. Answer the following questions: A. At what time will people begin having to wait in line before getting served (because the volume of people arriving has become too great)? Answer: 3.25 hours after opening. B. When is the line longest? Answer: 5 hours after opening. F-1 -10 C. How many people are in the line at the time when it's the longest? Answer: 20 people. D. When does the line vanish? 110 10.8 2,28) 11