If an area has shallow, intermediate, and deep earthquakes, what can you infer about the area?

Please note all correct answers:

a. It is near a subduction zone.

b. It is at a divergent plate boundary.

c. The shallow earthquakes will be closer to the trench.

d. The direction in which the earthquakes get deeper is also the direction the oceanic plate is subducting.

e. The area has the potential for large earthquakes.

f. There must be magma moving in the Earth to create this variety of earthquake depths.