A mechanical wave generator creates continuous, periodic surface waves in a ripple tank containing water. The waves travel through a deep-water region with a speed \(v_{\text{deep}}\), then cross a straight boundary into a shallow-water region where the wave speed is \(v_{\text{shallow}}\), such that \(v_{\text{shallow}} < v_{\text{deep}}\). Which of the following correctly describes how the wavelength of the waves in the shallow water compares to their wavelength in the deep water, and provides the correct physical justification?