A non-luminous object...

• A. Gives off light.
• B. Reflects light.
• C. Does not give off its own light.
• D. Transmits light.

Answer: (C)

A non-luminous object does not produce light on its own. It only becomes visible because light from another source shines on it and is reflected into your eyes or, if it’s transparent, passes through it. That’s why the defining idea is that it does not emit its own light. For example, the Moon shines in our sky because it reflects sunlight, not because it emits light itself. Emitting light would describe a luminous object, and transmitting light describes how some materials let light pass through but doesn’t define why something is non-luminous.