Reggie accidentally left his books on top of his car before he left for class. The books stayed on top of his car while he was driving north on Oak Avenue. Then, when he made a sharp turn eastward onto Harris Lane, his books fell off the top of his car and onto the street. Which of the following best explains why Reggie's books fell? A. The Earth's magnetic field held the books on Reggie's car while he headed north. When he turned east, the magnetic pull faded, causing the books to fall. B. Heat energy from the sun caused Reggie's books to slide off the top of his car and fall. C. When Reggie's car turned eastward, his books continued moving northward, causing them to slide off the top of his car. D. The force of gravity caused Reggie's books to slide across the top of his car and fall.