A position-time graph is shown below: A Position versus Time graph is shown with y-axis labeled position in centimeters up to 15 and x-axis labeled time in seconds up to 10. A straight line connects the points 0, 0 and 3, 3. A horizontal line connects points 3, 3 and 6, 3. A straight line connects 6, 3 and 10, 11. Which statement accurately describes the speed of the object in the graph above over the 10 seconds? a Speed is decreasing. b Speed is constant. c Speed is not constant. d Object is at rest