A ray of light travels from air to water. The refeactive index of water is given by the expression

• A.\(\frac{\text{velocity in water}}{\text{velocity in air}}\)
• B.\(\frac{\text{sine of angle of refraction}}{\text{sine of angle of incidence}}\)
• C.\(\frac{\text{apparent depth}}{\text{real depth }}\)
• D.\(\frac{\text{wavelength in air}}{\text{wavelength in water}}\)