Answer:
Option (D)
Explanation:
The velocities of the seismic waves namely the P and S waves, that propagates from the focus of an earthquake, increases with the increasing density of the earth's internal layers. As the depth of the earth increases, the density also increases and at the boundaries like the crust-mantle boundary, mantle-core boundary, and outer core-inner core boundary. The seismic wave velocities jumps abruptly at these boundaries, but gradually increases with the depth.
Thus, the correct answer is option (D).
