Answer to Question 1
Body waves are categorized as either P waves or S waves on the basis of their mode of propagation through Earth. P waves, or primary waves, result from the compression of material in Earth's interior. The material is alternately compressed and, as the wave travels away, stretched. Thus, a P wave travels as a series of compressions and expansions in the overall direction of wave movement, similar to the way sound travels or to the response of a spring or a Slinky. S waves, which are also called secondary or shear waves, are transmitted as displacements perpendicular to the overall direction of wave travel, like the movement of a wave on a string.
Answer to Question 2
C