Fact 1: Alight bulb is used for seeing in the dark.

Fact 2: An electric light bulb is a light source.

Given the two facts above, answer the question "A what is used for seeing in the dark?" with the following options: 
- darkness source
 - our nearest star
 - light source
 - shade source
 - energy barrier
 - energy
 - photons
 - blackout curtain


 

   light source      