Answer:
Option (A)
Explanation:
The idea of moving continents was first proposed by Alfred Wegener which was known as the continental drift theory. He gave many pieces of evidence in support of this theory but he was unable to explain the main mechanism behind this plate motion.
This theory was later modified by the plate tectonic theory that was successful in explaining the reason behind the motion of the plates. According to the plate tectonic theory, the lithospheric plates of the earth move constantly over the layer of asthenosphere due to the generation of convection current within the mantle. These currents are initiated from the heat supplied by the core of the earth.
Thus, the correct answer is an option (A).
