When a body falls freely towards the earth, then its total energy

The correct option is C

remains constant

The explanation of the correct option:

In the case of option (C),

1. The total energy of anybody is the sum of kinetic energy and potential energy.
   $TE=KE+PE$
2. When a body falls freely towards the earth; the kinetic energy of the body increases and the potential energy of the body decreases.
3. According to the law of conservation of energy, energy can only be transformed from one form of energy to another and cannot be created or destroyed. This indicates that unless energy is added from the outside, a system always has the same quantity of energy. However, by the law of conservation of energy total energy of the body remains constant.
4. A body's total energy remains constant while it falls freely towards the ground, that is, the sum of the body's potential and kinetic energy remains constant at all times.

Hence, the correct option is C.