In the Following Graph,why Does the Line for S-Waves NOT

In the following graph,why does the line for S-waves NOT appear in the outer core?

A) S-waves can't travel through the outer core because it is solid.
B) S-waves can't travel through the outer core because it is liquid.
C) S-waves disappear after being reflected at the core-mantle boundary.
D) S-waves can't travel that far into the Earth due to the high amount of iron.