Final answer:
Three recording stations are needed to find an epicenter.
Step-by-step explanation:
The number of recording stations needed to find an epicenter is Three (C).
Three recording stations are typically required to determine the location of an epicenter. By comparing the arrival times of the P- and S-waves at each station, the distance to the epicenter can be calculated.
Using the difference in arrival times, the distance to the epicenter is determined by calculating the time difference and multiplying it by the speed of seismic waves. With three or more recording stations, the intersection of the calculated distances can pinpoint the epicenter location.