Study the image of a seismic graph.
Graph of P & S Wave Travel Times, showing Travel time in minutes across distance in kilometers for P and S waves. S wave starts at zero kilometers, zero minutes, and increases to 10,000 kilometers, 25 minutes. P wave starts at zero kilometers, zero minutes and increases to 10,000 kilometers, 13 minutes.
About how far does the S wave travel through Earth in 13 minutes?
2,000 km
4,000 km
6,000 km
8,000 km