Which image shows the place where the pressure and density of the atmosphere would be lowest?

The image of the mountains ( snow mountains) is the place where the  pressure and density of the atmosphere would be lowest.

Explanation:

Air density can be described as how closely the molecules of air are packed.

The density of the air and air pressure decreases with the increase in altitude.

This is because at higher altitudes there is lesser air that is pushing down from above and gravity is hence weaker. As a result, air molecules spread more and the air density and pressure decreases.