A sea wave meets a cliff face. The crest of the wave reaches the cliff once every $6.0\,\text{s}$. The horizontal separation between a crest and the neighbouring trough of the wave is $4.5\,\text{m}$. Calculate the speed of the wave.
- A$0.67\,\text{m s}^{-1}$
- B$0.75\,\text{m s}^{-1}$
- C$1.3\,\text{m s}^{-1}$
- D$1.5\,\text{m s}^{-1}$