Answer the following question given this paragraph: 

The most common type of mirage is an illusion that light from faraway objects is reflected by a pool of water that is not really there. Mirages are generally observed in deserts, when there is a hot layer of air near the ground. Given that the refractive index of air is lower for air at higher temperatures, explain how mirages can be formed.


Q: What term is used to describe  an illusion that light from faraway objects is reflected by a pool of water that is not really there?

 Choices:

- version

- prototype

- Mirror

- mirage

A:
mirage
