Which of the following is true?
A. The Earth exerts a gravitational force on the Moon, but the Moon does not exert a gravitational force on the Earth.
B. The Earth and Moon both exert a gravitational force on each other.
C. The Moon exerts a gravitational force on the Earth, but the Earth does not exert a gravitational force on the Moon.
D. The Earth and Moon do not exert gravitational forces.