**Core Concept**
Vitamin C, also known as ascorbic acid, is an essential nutrient required for various bodily functions, including collagen synthesis, iron absorption, and immune function. Its deficiency can lead to scurvy, a disease characterized by connective tissue weakness and impaired wound healing.

**Why the Correct Answer is Right**
Vitamin C plays a crucial role in the hydroxylation of proline and lysine residues in collagen, a process necessary for cross-linking collagen fibers. Without sufficient vitamin C, collagen synthesis is impaired, leading to the characteristic symptoms of scurvy, including joint pain, fatigue, and poor wound healing. Additionally, vitamin C deficiency can cause impaired iron absorption, leading to anemia.

**Why Each Wrong Option is Incorrect**
**Option A:** Scurvy is indeed caused by vitamin C deficiency, so this option is incorrect.
**Option B:** Impaired collagen synthesis is a direct consequence of vitamin C deficiency, making this option incorrect.
**Option C:** Anemia caused by impaired iron absorption is a known consequence of vitamin C deficiency, making this option incorrect.

**Clinical Pearl / High-Yield Fact**
Vitamin C deficiency can also impair the absorption of non-heme iron, leading to anemia. This is because vitamin C is required for the reduction of ferric iron to ferrous iron, which is then absorbed by the intestine.

**Correct Answer:** D.