Which of the following may be used to explain a mirage?
I. Layers of air near the road surface have varying refractive indices in hot weather
II. Road surfaces sometimes becomes invisible in hot weather
III. Light from the sky can be refracted upwards after coming close to the road surface.

A.

I and III only

B.

II and III only

C.

II only

D.

I, II and III

Correct answer is A

No explanation has been provided for this answer.