What happens at the Pacific Ring of Fire which circles the Pacific Ocean from the west coast of North and South America to the east coast of Asia?

Geothermic gradient is the rate of increasing temperature with respect to increasing the depth in the earths interior. away from tech tonic plates boundaries, it is about 25-40 c/km (72-87 degrees f/mi) of depth near the surface in most of the world.

Ithink d would be correct