Assertion :-Any population has built in variation in characteristics.
Reason :-Variations are always stable and inheritable

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Answer

To solve the question, we need to evaluate the assertion and the reason provided, and determine their truthfulness and relationship.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "Any population has built-in variation in characteristics."
- This is true because genetic variation within a population is essential for evolution. Variations arise due to mutations, genetic recombination during sexual reproduction, and other factors.

2. **Understanding the Reason**:
- The reason states that "Variations are always stable and inheritable."
- This statement is false. While some variations can be inheritable, they are not always stable. Variations can change over generations due to environmental factors and other influences.

3. **Evaluating the Options**:
- **Option 1**: Both assertion and reason are true, and the reason is the correct explanation of the assertion. (False)
- **Option 2**: Both assertion and reason are true, but the reason is not the correct explanation of the assertion. (False)
- **Option 3**: The assertion is true, and the reason is false. (True)
- **Option 4**: Both assertion and reason are false. (False)

4. **Conclusion**:
- The correct answer is **Option 3**: The assertion is true, and the reason is false.