The correct response is: Both waves cause earthquakes.
P-waves (primary waves) and S-waves (secondary waves) are both types of seismic waves generated by earthquakes. However, P-waves move the ground in the direction they travel, while S-waves move the ground perpendicular to their direction of travel. Therefore, the other options regarding the movement of the ground are not accurate for both types of waves. Additionally, while seismic activity can influence oceanic areas, it's not exclusive to those environments.