Step 1: Understanding the P-S conversion.
As seismic waves travel through different layers of the Earth, the material properties, such as density and state (solid or liquid), cause the waves to change character. P-waves can travel through both solid and liquid, while S-waves can only propagate through solids. In the solid inner core, the P-wave converts to an S-wave.
Step 2: Correct Phase Identification.
The correct phase that describes this conversion is PKJKP, as it involves the change from P-wave to S-wave as the seismic wave passes through the core.
Final Answer: \boxed{(B)}