Gravitation
Electricity
Magnetism
Light
Answer is Right!
Answer is Wrong!
The correct answer is D. Light.
A photon is a quantum of light. It is a tiny particle that carries energy and momentum. Photons are emitted by atoms and molecules when they are excited. They can also be absorbed by atoms and molecules, causing them to change their energy levels.
Gravitational waves are not quantized, meaning that they do not come in discrete units. Instead, they are continuous waves that can have any amplitude.
Electricity and magnetism are both fundamental forces of nature. They are not quantized, meaning that they do not come in discrete units. Instead, they are continuous fields that can have any strength.
In conclusion, the only fundamental unit/quantum of the options given is light.