Assertion: The number `1.202 `has four significant figure and the number `0.0024` has two significant figure.
Reason: All the zero digits are significant.

Options

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

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding Significant Figures**:
- Significant figures are the digits in a number that contribute to its precision. This includes all non-zero digits, any zeros between significant digits, and any trailing zeros in the decimal part.

2. **Analyzing the Assertion**:
- The assertion states that the number `1.202` has four significant figures.
- In `1.202`, the digits are:
- `1` (significant)
- `2` (significant)
- `0` (significant because it is between two significant digits)
- `2` (significant)
- Therefore, `1.202` indeed has **four significant figures**. This part of the assertion is **true**.

3. **Analyzing the Second Part of the Assertion**:
- The assertion also states that the number `0.0024` has two significant figures.
- In `0.0024`, the leading zeros (the `0`s before `2`) are not significant. They only serve to place the decimal point.
- The significant figures in `0.0024` are:
- `2` (significant)
- `4` (significant)
- Thus, `0.0024` has **two significant figures**. This part of the assertion is also **true**.

4. **Analyzing the Reason**:
- The reason states that "All the zero digits are significant."
- This statement is **false** because not all zeros are significant. For example, in `0.0024`, the leading zeros are not significant.

5. **Conclusion**:
- The assertion is true (both numbers have the correct number of significant figures), but the reason is false (not all zeros are significant).
- Therefore, the correct answer is: **Assertion is true, but the reason is false.**

### Final Answer:
- The assertion is true, and the reason is false.