A ball is dropped from the top of a tower in the absence of air resistance. Which statement correctly describes how its kinetic and potential energies change as it falls?
a) Kinetic energy increases, but potential energy decreases by a greater amount.
b) Both kinetic energy and potential energy remain constant.
c) Kinetic energy increases while potential energy decreases by the same amount.
d) Kinetic energy remains constant while potential energy decreases.