Why Is the Southern Hemisphere of Mars Believed to Be

Multiple Choice

Why is the southern hemisphere of Mars believed to be older than the northern?

A) The southern hemisphere is darker much like the lunar mare.
B) The southern hemisphere is more heavily cratered.
C) The northern hemisphere is higher, due to the Tharsis Bulge.
D) The northern hemisphere leans more away from the Sun in winter.
E) The south polar cap is much thicker than the north one.