help me please

A person is taking a walk along a straight path. Their velocity, D (in feet per second), which is a function of time I (in seconds), is given by the graph in Figure 1.2.19. a. What is the person's velocity when / = 2? when f = ?? b. Are there any times when the person's velocity is exactly D = 3 feet per second? If yes, identify all such times; if not, explain why. c. Describe the person's behavior on the time interval 4 5 1 $ 5