Which one of the following is NOT a luminous object ?

The correct answer is (d). The moon is not a luminous object. It is a non-luminous object that reflects light from the sun.

A luminous object is an object that emits its own light. Examples of luminous objects include the sun, stars, fireflies, and light bulbs.

A non-luminous object is an object that does not emit its own light. Examples of non-luminous objects include the moon, planets, and most of the objects in our daily lives.

The moon is a non-luminous object because it does not produce its own light. The moon reflects light from the sun, which is why we can see it at night.