Bending of the light rays, when they travelling from one medium to another is called refraction.
If light travels from one medium to another it frequency is unaltered but speed and wavelength is changed. Light undergo refraction when they travel from one medium to another. Light would bend away from the normal when travelling from denser to a rarer medium.
Hence, the options (a), (b) and (d) are wrong
Light would bend toward the normal. So, option (c) is the right answer.