Correct Answer: total internal reflection

Solution : The correct option is total internal reflection.

The phenomenon of total internal reflection (TIR) happens when light travelling through a denser media meets the border of a less dense medium at a sufficiently large angle, causing the light to be reflected into the denser medium. When the air near the ground is hotter than the air above it, mirages form. Because hot air is less dense than cold air, it has a lower refractive index. This implies that light rays travelling from the sky to the ground will deviate from their typical path as they move from cooler to hotter air.