Which of the following is a vitamin ?

Options

A. Glucose
B. Keratin
C. Maltose
D. Riboflavin

Explanation

To determine which of the following options is a vitamin, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Identify the Options**: The question presents four options. We need to evaluate each one to see if it qualifies as a vitamin.

2. **Evaluate Glucose**:
- Glucose is a simple sugar and a carbohydrate.
- It is classified as a monosaccharide.
- **Conclusion**: Glucose is not a vitamin.

3. **Evaluate Carotene**:
- Carotene is a pigment found in plants and is responsible for the orange color in carrots and other vegetables.
- It is a type of protein and is often associated with vitamin A.
- **Conclusion**: Carotene itself is not classified as a vitamin.

4. **Evaluate Maltose**:
- Maltose is a disaccharide sugar formed from two glucose units.
- It is also classified as a carbohydrate.
- **Conclusion**: Maltose is not a vitamin.

5. **Evaluate Riboflavin**:
- Riboflavin is also known as vitamin B2.
- It is a water-soluble vitamin essential for various bodily functions.
- It can be found in foods such as milk, green vegetables, and egg whites.
- **Conclusion**: Riboflavin is indeed a vitamin.

6. **Final Answer**: Based on the evaluations, the correct answer is **Riboflavin**.