The Pressure in the Atmosphere of Earth Varies with Altitude

The pressure in the atmosphere of Earth varies with altitude by:

A) decreasing smoothly with altitude, dropping by about half for every 5.5 km.
B) increasing over a small altitude range above the surface of Earth (about 1 km) and then decreasing smoothly with increasing altitude.
C) remaining constant up to the height of the highest mountains, then decreasing rapidly.
D) decreasing and increasing several times with increasing altitude, following the temperature variation.