A floating object on a lake is made to move up and down $18$ times in $12\,\text{s}$ by a passing boat. The wave produced by the boat has a wavelength of $48\,\text{cm}$. What is the velocity of these water waves?
- A$32\,\text{cm s}^{-1}$
- B$72\,\text{cm s}^{-1}$
- C$576\,\text{cm s}^{-1}$
- D$864\,\text{cm s}^{-1}$