Why Does Mars Have Less Heat Available (Relative to the Earth)to

Why does Mars have less heat available (relative to the Earth) to drive volcanic activity?

A) Mars is smaller than the Earth,and therefore cooled more rapidly
B) Compared to the Earth,Mars has a smaller area to volume ratio,
C) Larger planets cool more rapidly than smaller planets.
D) Mars lost most of its internal heat after colliding with a large,moon sized object.