"It is gravitational energy. Gravitational energy doesn't change forms, it just remains as gravity in the form of a potential"
(I just saw dis somewhere. Credits to the writer)
The correct answer is letter C - a pen spring being compressed
A pen spring which was being compressed does not describe or show potential energy being transferred into kinetic energy .
Option A is not the correct answer since the movement of the box going down a ramp is a clear example of potential energy transferred into kinetic energy. What we are looking is a scenario where a potential energy is transferred into kinetic energy.
Option B is not also the correct answer since the potential energy in the mango was changed into kinetic energy as it falls from a crate. The gravity changes the potential energy in the mango into a kinetic energy.
Option D is not the correct answer as the stretched rubber band which got loosened after stretching, stretches back to its resting state after it was loosened, hence, transfer of potential energy into kinetic energy was observed in the event.
Option C is an example of elastic potential energy. Elastic potential energy is the energy stored in an object when stretched, compressed, or twisted. This is clearly the correct answer since the spring was just only compressed and it was not actually released which will clearly show or portray potential energy being transferred into kinetic energy.