Here's a problem to solve: A teacher puts a cup of coffee into the cup holder of a car. When the car stops suddenly some of the coffee spills out of the cup. Which statement best explains why the coffee spills?

Among the 4 following options, which is the correct answer?

- A: The coffee stays in motion because the stopping force acts only on the car.
 
- B: The coffee stays in motion because a force from the cup holder pulls on the coffee.
 
- C: The stopping force on the car causes an equal and opposite reaction from the coffee.
 
- D: The stopping force causes the motion of the car to slow down and the motion of the coffee to speed up.
 