The function f, whose graph consists of two line segments, is shown. Which of the following are true for f on the open interval (a, b)? 1. The domain of the derivative of f is the open interval (a, b). II. f is continuous on the open interval (a, b). III. The derivative of f is positive on the open interval (a, c). OI only II only Ill only I and II only Y I and III only II and III only I, II, and III C + None of these statements are true.