Total internal reflection can take place when light travels from

Total internal reflection occurs only when two specific conditions are met. First, light must travel from a denser medium to a rarer medium. Second, the angle of incidence must be greater than the critical angle. In option A, diamond is optically denser than glass because it has a higher refractive index. Therefore, light is traveling from a denser to a rarer medium, making total internal reflection possible. In all other options, light is traveling from a rarer medium to a denser medium, such as air to water or water to glass. In these cases, light bends toward the normal and total internal reflection cannot occur.