Answer:
D. Tidal forces from the Sun on Venus's atmosphere
Explanation:
Venus is one of the two planets in the solar system that have a retrograde motion, with the other planet being Uranus. There have been lot of speculation about how and why this has happened, and there have been numerous theories. The most accepted theory is that Venus was once moving as all the other planets, but it gradually slowed down until it become static, and than started to spin in the opposite direction. The reason behind this is believed to be the Sun with its gravitational pull, and that its tidal forces managed to influence Venus's atmosphere so much, that it made it spin in the opposite direction over time.
