How Does the Elevation of the Tropopause Above the Tropics

How does the elevation of the tropopause above the tropics compare to its elevation above the poles and why does this occur?

A) It is lower above the tropics because the stratosphere is thicker over the tropics and so it compresses the troposphere.
B) It is lower above the tropics because the troposphere weighs more in the tropics and so it sinks.
C) It is higher above the tropics because the troposphere is hotter in the tropics,and this causes the air to rise to greater heights.
D) It is higher above the tropics because the stratosphere is thinner over the tropics and this allows the troposphere to expand.