Which Effect Is Now Thought to Be the MOST Likely

Multiple Choice

Which effect is now thought to be the MOST likely cause for the inclinations of spin axis of several of the planets such as Uranus (and even Earth) to their orbital planes?

A) the out-of-balance force on the spin axes of planets from their moons, some of which are very massive
B) a major collision with another planet-like body
C) the steady force on one hemisphere of the planet from the highly directional solar wind
D) tidal distortion and deflection caused by neighboring planets