Lemons have sour taste due to presence of:

Options

A. Acetic acid
B. Citric acid
C. Lactic acid
D. Oxalic acid

Explanation

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks why lemons have a sour taste.

2. **Understand the Composition of Lemons**: Lemons are known to contain various organic acids. The primary acid responsible for their sour taste is citric acid.

3. **Explain Citric Acid**: Citric acid is a weak organic acid that is commonly found in citrus fruits, including lemons. It is known for its tart flavor, which contributes to the sour taste of lemons.

4. **Consider Other Acids**: The question may provide options that include other acids such as acetic acid, lactic acid, and oxalic acid.
- **Acetic Acid**: Found in vinegar, not lemons.
- **Lactic Acid**: Present in curd, not lemons.
- **Oxalic Acid**: Found in leafy green vegetables, not lemons.

5. **Conclusion**: Since citric acid is the only acid among the options that is present in lemons and is responsible for their sour taste, the correct answer is citric acid.

**Final Answer**: Lemons have a sour taste due to the presence of **citric acid**.

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