Which of the Following Is Not Part of the Accepted

Multiple Choice

Which of the following is not part of the accepted driving mechanism of plate tectonic motions?

A) The Earth's unequal distribution of internal heat is what drives the mantle convection and provides the heat engine.
B) All of the heat for the mantle convection comes from small amounts of radioactive elements in the inner core.
C) Solid state convective flow in the rocky mantle, warm regions rising and cold regions sinking, is the basic driving force for plate motions.
D) Oceanic plates descend and constitute the downward- moving portion of Earth's internal convective flow.