Answer:
Correct Answer is A. volcanic activity and tectonic movement
Explanation:
The Great Rift Valley located in central and eastern Africa is a big Geological fracture, Its formation involved the Separation of tectonic plates in a process called Divergence, which also lead to volcanic activity.
In the Divergence process, the tectonic plates are expanded by the Earth's crust, Contrary to when two tectonic plates collide and form mountains, in a divergence process the plates are being separated, creating a big ditch or trench. When the rocks sink they form a "Graben" and volcanic cones from molten lava ascending because of the tectonic movement and pressure.
