Assertion : After 24h. Toddy becomes unpalatable .
Reason : Toddy left for a few hours undergoes fermentation .

Options

A. If both Assertion and Reason are true and the reason is the correct explanation of the assertion , then mark (1) .
B. If both Assertion and Reason are true but the reason is not the correct explanation of the assertion , then mark (2).
C. If assertion is true but Reason is false , then false , then mark(3).
D. If both assertion is true Reason are false , then Mark (4).

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that "After 24 hours, toddy becomes unpalatable." This implies that the drink is no longer enjoyable or suitable for consumption after this time period.

2. **Understanding the Reason:**
- The reason provided is that "Toddy left for a few hours undergoes fermentation." This means that when toddy is left out, it continues to ferment, which alters its taste and quality.

3. **Analyzing Toddy:**
- Toddy is a traditional alcoholic beverage made from the sap of palm trees, particularly in South India. It naturally contains alcohol and undergoes fermentation due to the action of yeast.

4. **Fermentation Process:**
- During fermentation, sugars in the sap are converted into alcohol and carbon dioxide by yeast. Initially, toddy may contain around 6% alcohol.

5. **Chemical Changes After 24 Hours:**
- After being left for 24 hours, the fermentation process continues, leading to the production of acetic acid (similar to vinegar). The concentration of acetic acid can reach about 4-5%, making the drink acidic.

6. **Conclusion on Palatability:**
- The presence of acetic acid is what makes the toddy unpalatable. A drink with such acidity is generally considered unpleasant to consume.

7. **Final Evaluation:**
- Both the assertion and the reason are true. The reason correctly explains why the assertion is valid: the fermentation process leads to the production of acetic acid, which makes the toddy unpalatable after 24 hours.

**Final Answer:**
Both the assertion and reason are true, and the reason is the correct explanation of the assertion.

---