Figure 9 shows the layers inside the Earth. An earthquake occurs at the position shown. Which letter shows the position where only P-waves will be detected? Give a reason for your answer.

P-waves are longitudinal and can travel through both solids and liquids. S-waves are transverse and can only travel through solids. The Earth has a liquid outer core. When an earthquake occurs, both P-waves and S-waves travel out. - To reach positions A, B, and D, the waves can travel through the solid mantle. Both P and S waves will be detected. - To reach position C, the waves must pass through the core. P-waves can pass through the liquid outer core (though they are refracted), but S-waves are stopped completely. This creates an "S-wave shadow zone" on the side of the Earth opposite the earthquake. Therefore, at position C, only P-waves will be detected.