Which of the following vitamin is called retinol?

Answer: Option D

Vitamin A is called retinol.
Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal, retinoic acid, and several provitamins A carotenoids.
It is essential for embryo development and growth, maintenance of the immune system, and vision, where it combines with the protein opsin to form rhodopsin, the light-absorbing molecule necessary for both low-light and color vision.