Shown in the diagram is a distance - time graph for a car. Which of the following graphs best represents the car’s motion during this entire 10-second period? Look carefully at the car's motion A) The car accelerates for 10 seconds B) The car moved forward at a constant speed for 6 seconds before moving backwards C) The car accelerated for 6 seconds and continued at a constant speed D) The car moved forward at a constant speed for 6 seconds and then stopped moving suddenly