As two oceanic plates diverge at mid-ocean ridges, melting of the rising mantle occurs due to:

A) decompression
B) the addition of heat
C) the addition of water

Decompression

The reduction in pressure experienced by a body, often leading to the expansion of gases held in solution under higher pressure.

Mid-ocean Ridges

Mountainous formations under the sea, created by the shifting of earth's plates, which result in new ocean crust through volcanic processes.

Rising Mantle

The upward movement of the Earth's mantle, often leading to volcanic activity.