The Tharsis Rise on Mars,a Region That Is Higher Than

The Tharsis rise on Mars,a region that is higher than the surrounding plain by about 5 km (over 16,000 ft) ,was caused by

A) the collision of two tectonic plates.
B) the focusing of seismic waves from the impact of a massive asteroid at the diametrically opposite point on Mars.
C) an upwelling magma plume in Mars's interior,which has raised this whole region.
D) erosion of the surrounding plain by massive floods.