Because of tidal forces and an eccentric orbit, Mercury: A. Rotates on its axis 1 time for every 1 time it revolves around the sun B. Rotates on its axis 2 times for every 1 time it revolves around the sun C. Rotates on its axis 3 times for every 1 time it revolves around the sun D. Rotates on its axis 3 times for every 2 times it revolves around the sun E. Rotates on its axis 2 times for every 3 times it revolves around the sun

Answer: D. Rotates on its axis 3 times for every 2 times it revolves around the sun

Explanation:

Mercury's orbit is quite eccentric and this causes the planet to be in a 3:2 orbital resonance. This means Mercury roates three times on its axis every two Mercurian years. This is also known as tidal locking.

In addition, the high eccentricity of this planet's orbit causes this resonance to be stable in the perihelion (when Mercury is closer to the Sun in its orbit), when the solar tide is strongest.

Therefore, the correct option is D.