**Core Concept**
Collagen is the most abundant protein in the human body, forming a strong scaffold for connective tissue in bones, skin, tendons, and ligaments. Its formation involves a complex process of gene expression, protein synthesis, and post-translational modification, which can be disrupted by various factors including nutritional deficiencies.

**Why the Correct Answer is Right**
Scurvy, caused by a deficiency of vitamin C, is a classic example of a disorder affecting collagen formation. Vitamin C (ascorbic acid) is essential for the hydroxylation of lysine and proline residues in collagen, which are necessary for the stabilization of the collagen triple helix. Without sufficient vitamin C, the lysyl hydroxylase enzyme is impaired, leading to the accumulation of unhydroxylated lysine residues and the formation of defective collagen fibrils. This results in weakened connective tissue, manifesting as bleeding gums, joint pain, and poor wound healing.

**Why Each Wrong Option is Incorrect**
**Option B:** Hunter's syndrome is a genetic disorder caused by a deficiency of the enzyme iduronate-2-sulfatase, which leads to the accumulation of glycosaminoglycans (GAGs) in the body. While it affects the structure of connective tissue, it does not primarily involve a defect in collagen formation.

**Option C:** Marfan's syndrome is a genetic disorder affecting the gene that codes for fibrillin-1, a protein essential for the formation of elastic fibers in connective tissue. Although it shares some clinical features with scurvy, such as joint hypermobility and skin fragility, it is not directly related to collagen formation.

**Option D:** This is incorrect because only scurvy among the listed options directly affects collagen formation.

**Clinical Pearl / High-Yield Fact**
Remember that vitamin C deficiency can lead to impaired collagen synthesis, resulting in fragile connective tissue and increased risk of bleeding and poor wound healing. This is a classic example of how a nutritional deficiency can have far-reaching consequences for human health.

**✓ Correct Answer: A. Scurvy**