Let f(x) be the function whose graph is shown. The x y-coordinate plane is given. A curve with 3 parts is graphed. The first part is linear, begins at the closed point (0, 5), goes horizontally right, and ends at the closed point (3, 5). The second part is linear, begins at the closed point (3, 5), goes up and right, and ends at the closed point (5, 7). The third part is a curve, begins at the closed point (5, 7), goes down and right becoming less steep, changes direction at the point (7, 6), goes up and right becoming more steep, and exits the window in the first quadrant. Determine f?'(x) for x = 1, 2, 4, and 7. (a) f?'(1) = (b) f?'(2) = (c) f?'(4) = (d) f?'(7) =