To Study Traffic Flow Along a Major Road, the City

Multiple Choice

To study traffic flow along a major road, the city installs a device at the edge of the road at 3:00a.m.The device counts the cars driving past, and records the total periodically.The resulting data is plotted on a graph, with time (in hours since installation) on the horizontal axis and the number of cars on the vertical axis.The graph is shown below; it is the graph of the function C(t) = Total number of cars that have passed by after t hours.From the graph, estimate C'(6) .

A) 600
B) 900
C) 1200
D) 1500