Which of the following is a water soluble vitamin? 

Vitamin C

The correct answer is option 2. Vitamin C.

Among the vitamins listed, Vitamin C is the water-soluble vitamin.

1. Vitamin A: This is a fat-soluble vitamin. It is absorbed with dietary fats and stored in the liver and adipose tissue. Examples include retinol and beta-carotene.

2. Vitamin C: This is a water-soluble vitamin. It is soluble in water and not stored in the body; excess amounts are excreted in the urine. Vitamin C, also known as ascorbic acid, is crucial for collagen synthesis, antioxidant protection, and immune function.

3. Vitamin D: This is a fat-soluble vitamin. It is important for calcium and phosphorus metabolism and bone health. It can be synthesized in the skin in response to sunlight and is stored in the liver and fat tissues.

4. Vitamin E: This is also a fat-soluble vitamin. It acts as an antioxidant, protecting cells from damage. It is stored in fat tissues and the liver.

Summary: Vitamin C is the only water-soluble vitamin among the options provided.