The correct option is B decreases
Atmospheric pressure decreases with increases in the altitude. As we know that the density of air becomes more near the surface of the earth (due to gravity) and begins to lighten as we go to higher altitudes and eventually leads to empty space, i.e. outside the atmosphere of the earth. Thus, the atmospheric pressure is high at lower altitudes, the density being higher. The atmospheric pressure is low at higher altitudes, the density being lower.