Which one is sugar acid

Options

A. Vitamin C
B. Vitamin K
C. Vitamin D
D. Vitamin E

Answer

### Step-by-Step Solution:

1. **Understanding Sugar Acids**:
- Sugar acids are derived from sugars and contain a carboxyl group (-COOH) at one or both ends. They can be classified as monosaccharides that have been oxidized to form carboxylic acids.

2. **Identifying the Options**:
- The options provided are:
- A) Vitamin C
- B) Vitamin K
- C) Vitamin D
- D) Vitamin E

3. **Analyzing Each Option**:
- **Vitamin C**: Also known as ascorbic acid, it is a sugar acid. It is formed by the oxidation of an aldose sugar, resulting in a carboxylic acid.
- **Vitamin K**: This vitamin is not a sugar acid; it is involved in blood clotting and has a different structure.
- **Vitamin D**: This vitamin is related to calcium metabolism and is not classified as a sugar acid.
- **Vitamin E**: This vitamin is an antioxidant and does not have the characteristics of a sugar acid.

4. **Conclusion**:
- Based on the analysis, the only option that qualifies as a sugar acid is **Vitamin C** (ascorbic acid).

### Final Answer:
- The sugar acid is **Vitamin C**.