Final answer:
The total mechanical energy of a freely falling body remains constant as potential energy is converted into kinetic energy. The conservation of mechanical energy ensures the sum of both energies is conserved throughout the fall. Option C is the correct answer.
Step-by-step explanation:
When a body falls freely towards the Earth, the total mechanical energy of the body remains constant, assuming there is no air resistance. As the body accelerates due to gravity, its potential energy due to its position is converted into kinetic energy due to its motion. At any point during the fall, the sum of potential energy and kinetic energy is constant because energy cannot be created or destroyed, only transformed from one form to another; this is known as the conservation of mechanical energy principle.
At the beginning of the fall, the body has its maximum potential energy and minimum kinetic energy. As it falls, the potential energy decreases while the kinetic energy increases proportionally, so that the sum remains the same. The velocity of the falling body increases due to the acceleration under gravity, but the acceleration itself remains constant and directed towards the Earth's center.
In summary, the correct option is (c) remains constant, as the total energy of the body during free fall does not increase or decrease but is conserved.