What formed the great rift valley?

1: volcanic activity and tectonic movement
2: a massive earthquake 200 years ago
3: a mountain range west of the valley
4: a massive basin in the valley's center

What's a recharge area? a. the part of an aquifer where groundwater meets a lake or stream b. the part of an aquifer where surface water reaches the water table c. the part of an aquifer that's located between two aquicludes d. the part of an aquifer that's located at a lower elevation