Why Is the Surface of Venus Hotter Than That of Mercury

Why is the surface of Venus hotter than that of Mercury, even though Mercury is much closer to the Sun?

A) Venus experiences continuous volcanic activity and the release of hot lava onto the surface.
B) The thick carbon dioxide atmosphere of Venus has prevented re-emission into space of the heat absorbed from sunlight.
C) Chemical reactions within the thick clouds and dense atmosphere of Venus are continuously supplying heat to the surface.
D) Venus rotates rapidly, which ensures that its entire surface is being heated regularly and uniformly.