What Is the Cause of the Great Mountain Ranges on Earth

What is the cause of the great mountain ranges on Earth, such as the Rockies, the Andes, and the Himalayas?

A) In the carving of continents during ice ages, the mountains were left behind as "islands" in a sea of glaciers.
B) Heat from Earth's interior caused Earth's crust to expand and then crumple.
C) Two tectonic plates are being pushed apart by molten rock that is being forced up between them.
D) Two tectonic plates that are moving at different velocities across the face of Earth collide.