conduction in the ocean convection in the mantle radiation from the solid core evaporation at mid-ocean ridges
I gave my students this multiple choice question: Heat from deep in Earth's interior is transferred to its crust by which of the following?

Only one answer is correct among these 4 choices:
- conduction in the ocean
- convection in the mantle
- radiation from the solid core
- evaporation at mid-ocean ridges

Could you tell me which one is correct?

convection in the mantle