How Do Earthquake-Generated Waves Help Scientists Deduce the Internal Structure

How do earthquake-generated waves help scientists deduce the internal structure of Earth?

A) Primary waves are detected at a seismometer when they pass through solid or liquid materials.
B) Secondary waves are detected at a seismometer when they pass through solid materials.
C) The path of waves bends as they travel through material of different density.
D) Earthquake-generated waves can be detected and studied anywhere in the world.
E) All of these choices are correct.