The correct answer is - B. convection currents in Earth's mantle.
The movement of the Earth's tectonic plates is driven by the convection currents. The convection currents appear in the mantle layer, and they are currents made out of molten metals with high temperature and very high pressures.
Those high temperatures and pressures have resulted in cracking the crust on the surface of the Earth, thus creating multiple tectonic plates, some very large, some very small.
The pressure from the convection currents is so high that it actually manages to move the plates in certain direction, making them collide/subduct, slide past one another, or move away from one another, shaping up the physical geography of our planet.
The explanation is that the two continents must have been once connect to form a super continent called Pangaea. The fossil was part of a herd that probably crossed Pangaea. When Pangaea split animals were on both sides. That is why fossils found in South America are found in Africa.
Regolith is made of organic material which supports plant growth so it is true