Which of the following vitamins is essential for normal vision?

Correct answer: (d) Retinol

Explanation

Retinol (Vitamin A) is essential for normal vision, especially in dim light.

It forms rhodopsin, the light-absorbing pigment in the retina; its deficiency causes night blindness.

Folic acid, riboflavin (B2) and niacin (B3) are B vitamins not primarily linked to vision.