Final answer:
An object at rest gains kinetic energy as it accelerates towards a massive object due to gravity, thereby increasing its velocity and kinetic energy.
Step-by-step explanation:
When an object that is initially at rest starts being gravitationally pulled toward a massive object, its kinetic energy increases. This happens because as the object accelerates due to gravity, it starts moving faster towards the massive object, and since kinetic energy is defined as ½mv² (where m is the mass and v is the velocity), an increase in velocity leads to an increase in kinetic energy. Hence, the correct option here is c) it increases.