Final answer:
The subject of this question is Geography, and it is asking about the movements and limits of tectonic plates. Divergent boundaries occur when plates move away from each other.
Step-by-step explanation:
The subject of this question is Geography because it is asking about the movements and limits of tectonic plates. Tectonic plates and their boundaries are key concepts in the field of geography.
When discussing tectonic plate boundaries, we must distinguish between divergent, convergent, and transform boundaries. Divergent boundaries occur when plates move away from each other, convergent boundaries occur when plates move toward each other, and transform boundaries occur when plates slide past each other.
In the context of the options provided in the question, the correct answer is a) the movement is one of separation. It occurs when two plates move away from each other.