During an athletics race, the starter fires the starting pistol. A wall is located $60\ \text{m}$ from the starter. Use a speed of sound of $330\ \text{m s}^{-1}$. How long after the pistol is fired does the starter hear the echo reflected from the wall?
- A$0.18\ \text{s}$
- B$0.36\ \text{s}$
- C$2.8\ \text{s}$
- D$5.5\ \text{s}$