**Question:** The only water-soluble vitamin stored in the body

A. Vitamin A (Retinol)
B. Vitamin D
C. Vitamin E
D. Vitamin K

**Core Concept:** Water-soluble vitamins are easily soluble in water and cannot be stored in the body for long periods. Instead, they are excreted via urine. Vitamins A, D, E, and K are all essential micronutrients that play crucial roles in various physiological processes.

**Why the Correct Answer is Right:** Vitamin D is stored in the body, primarily in adipose tissue, and can be produced endogenously through exposure to sunlight. Vitamin E is stored in the liver and adipose tissue, but the correct answer should be the vitamin stored in the body without being water-soluble. Vitamin A is stored in the liver and adipose tissue, but it is not the only water-soluble vitamin. Vitamin K is stored in the liver, but it is not water-soluble.

**Why Each Wrong Option is Incorrect:** Vitamins A, D, and K are all fat-soluble and can be stored in the body, making them irrelevant to the question. Vitamin E is also stored in the body, but it is not water-soluble.

**Core Concept:** Vitamin C is a vitamin that is not stored in the body due to its high water solubility. It is mainly absorbed in the small intestine and mainly excreted via urine.

**Why the Correct Answer is Right:** Vitamin C is a water-soluble vitamin that cannot be stored in the body. It is essential for collagen synthesis and antioxidant defense, among other functions.

**Why Each Wrong Option is Incorrect:** Vitamins A, D, E, and K are all fat-soluble and stored in the body. Vitamin B12 is not water-soluble and is not the correct answer for this question.

**Clinical Pearl:** Maintaining adequate vitamin C intake is crucial for preventing scurvy, a disease characterized by impaired wound healing, easy bruising, and fatigue. Ensuring a balanced diet that includes citrus fruits, berries, and bell peppers can contribute to optimal vitamin C levels in the body.