The correct option is C Retinal is a derivative of Vitamin C
Retinol pigment is an aldehyde of vitamin A. Retinol epithilium sheilds the retina from excess incoming light.
Retina is the innermost, light sensitive layer of the eyeball, on which images are formed. They contain Photoreceptors which are light-sensitive cells.
Rods are responsible to detect light in dim light (black and white) enabling night vision. They contain a pigment called Rhodospin which is light sensitive.
Cones are responsible to detect coloured light. There are green, blue and red cones. Red is used to respond to long wavelengths. Blue is used to respond to short wavelengths and Green is used to respond to medium lengths. Cones are closely packed to allow the perception of details but cannot work well in dim light.