Option 1: Vitamin A does not contain nitrogen. It is a fat-soluble vitamin that plays a role in vision, immune function, and cell growth.

Option 2: Vitamin B does contain nitrogen. It is a group of water-soluble vitamins that are essential for various bodily functions, such as energy production, nerve function, and red blood cell formation.

Option 3: Vitamin C does not contain nitrogen. It is a water-soluble vitamin known for its role in immune function, collagen synthesis, and antioxidant properties.

Option 4: Vitamin D does not contain nitrogen. It is a fat-soluble vitamin that helps regulate calcium and phosphorus levels in the body and is important for bone health.

Therefore, the correct answer is option 2 – Vitamin B. It is the only option among the choices that contains nitrogen.