Which represents a force pair?
A. A golf club hits a golf ball. Gravity pulls the ball back down to Earth.
B. A book pushes down on a table, and gravity pulls the book toward the floor.
C. A boy's foot pushes down on a bicycle pedal. The pedal pushes up on his foot.
D. A person's foot pushes on the floor, and the person's weight pushes on the floor.
