The Reason That Olympus Mons, the Tallest Mountain on Mars

Multiple Choice

The reason that Olympus Mons, the tallest mountain on Mars, is taller than Mount Everest (the tallest mountain on Earth) is that:

A) the gravity on Mars is less, so a larger mass can support itself against its own weight
B) Mars has a much larger molten core than the Earth
C) there are no continental plates that move sideways on Mars, while there are such sliding motions on Earth
D) the Earth's Moon has a much stronger pull than the moons of Mars
E) more than one of the above