First fermented acid is

Options

A. Gluconic acid
B. Lactic acid
C. Fumaric acid
D. All the above

Answer

**Step-by-Step Solution:**

1. **Understanding Fermented Acids**: Fermented acids are organic compounds produced through the fermentation process, where microorganisms like bacteria convert sugars into acids.

2. **Identifying the Options**: The options given are:
- Gluconic acid
- Lactic acid
- Fumaric acid
- All of the above

3. **Researching Lactic Acid**: Lactic acid is produced by the fermentation of sugars by specific bacteria, particularly the Lactobacillus species. This process is commonly associated with dairy products like yogurt and cheese.

4. **Historical Context**: Lactic acid was the first fermented acid discovered and studied. The Lactobacillus bacteria were first identified in milk fermentation processes, which is why they are named after milk (lacto-).

5. **Conclusion**: Based on the information gathered, lactic acid is recognized as the first fermented acid due to its historical significance and the role of Lactobacillus bacteria in its production.

6. **Final Answer**: Therefore, the correct answer to the question "First fermented acid is" is **lactic acid**.

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