Which statement about seismic waves is false?
a. p waves travel faster, so the gap between their arrival times gives the source's distance.
b. only p waves can be detected in the shadow zone.
c. close to the epicenter, both s and p waves can be recorded.
d. both s and p waves can be detected by seismographs.
e. s waves are blocked by the fluid outer core and cannot be observed on the other side of the planet from the epicenter.