A water wave travels from shallow water to deep water and speeds up. Which of the following statements best describes the wave's behaviour as it changes mediums?
a) The frequency of the wave is higher in the shallow water and lower in the deeper water.
b) The frequency of the wave is lower in the shallow water and higher in the deeper water.
c) The wavelength is longer in the shallow water and shorter in the deep water.
d) The wavelength is shorter in the shallow water and longer in the deep water.
e) The wavelength is unaffected.