Final answer:
A white ceiling aids in room illumination due to the reflection of light, which allows for an even distribution of light throughout the room.
Step-by-step explanation:
A white ceiling aids in the illumination of a room mainly because of reflection. Reflection occurs when light waves bounce off a material. A white surface, like a ceiling, reflects light very efficiently because it does not absorb much of the light spectrum. This reflection helps to disperse light throughout the room, making it brighter.
As opposed to absorption, which captures the energy of light waves, reflection allows light to be redirected. This is why a white ceiling is preferable for illuminating a room rather than a ceiling of a darker color, which would absorb more light and make the room appear dimmer.
Moreover, the rough surface of typical white ceilings diffuses the reflected light, allowing for an even distribution of light, similar to the diffusion. This diffused reflection is beneficial for room lighting as opposed to the direct reflection one would observe with a mirror-like surface. Therefore, the correct answer to our given question is (c) reflection.