The figure shows the graph of the derivative of a function f. The domain of f is the closed interval [-3,3]. a. For what values of x in the open interval (-3,3) does f have a relative maximum? Justify your answer. b. For what values of x in the open interval (-3,3) does f have a relative minimum? Justify your answer. c. For what values of x is the graph of f concave up? Justify your answer. d. Suppose f(-3) = 0. Sketch a possible graph of f on the domain [-3,3].