## **Core Concept**
Vitamin C (ascorbic acid) plays a crucial role in the synthesis of collagen, a key structural protein found in connective tissue. Collagen synthesis involves the hydroxylation of proline and lysine residues, which is essential for the stability and formation of the collagen triple helix.

## **Why the Correct Answer is Right**
The correct answer, Vitamin C, is required for the activity of prolyl hydroxylase and lysyl hydroxylase, two enzymes critical for collagen synthesis. These enzymes catalyze the hydroxylation of proline and lysine residues in procollagen, which is necessary for the proper folding and stability of the collagen molecule. Without Vitamin C, collagen synthesis is impaired, leading to the clinical manifestations seen in scurvy, such as poor wound healing and fragile connective tissue.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Vitamin A is crucial for vision, immune function, and skin health but is not directly involved in collagen synthesis.
- **Option B:** Vitamin D is essential for calcium absorption and bone health but does not play a direct role in collagen synthesis.
- **Option D:** Vitamin E acts as an antioxidant, protecting cells from damage, but it is not directly involved in collagen synthesis.

## **Clinical Pearl / High-Yield Fact**
A key clinical correlation to remember is that scurvy, caused by Vitamin C deficiency, leads to impaired collagen synthesis. This results in symptoms such as poor wound healing, bleeding gums, and joint pain.

## **Correct Answer:** . Vitamin C