Venus Is Usually Described as a Runaway Greenhouse Effect World

Venus is usually described as a runaway greenhouse effect world, which is true in the sense that the atmosphere is mostly CO₂. However, the slow rotation of Venus produces a huge heat influx difference from the day to night side of the planet, which produces descending air on the night side and ascending air on the day side. Because the atmosphere is so dense, this means air rises to high elevations on the day side, and descends to surface on the night side. As a result, the night side of the planet is nearly as hot, or even hotter, than the day side. What would be the principal reason for this?

A) The air is so dense it has a large heat capacity.
B) As the air descends on the night side of the planet, it is heated by adiabatic compression to a very high temperature-a grand scale equivalent of Chinook or Santa Ana winds on Earth.
C) The winds must be very, very high, and transport the heat efficiently from one side of the planet to the other.
D) None of these makes sense.