Assertion: Gold and platinum occur in native state.
Reason: Gold and platinum are expensive metals

Options

A. Assertion is false but reason is true
B. Assertion is true but reason is false
C. Both assertion and reason are true, but reason is not a true explanation for assertion
D. Both assertion and reason are true and reason is the correct explanation for assertion

Answer

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

### Step-by-Step Solution:

1. **Identify the Assertion**:
- The assertion states that "Gold and platinum occur in native state."
- This means that these metals are found in their pure, uncombined form in nature.

2. **Evaluate the Assertion**:
- Gold and platinum are known as noble metals. They do not react easily with other elements, which is why they can be found in their native state in the Earth's crust.
- **Conclusion**: The assertion is **correct**.

3. **Identify the Reason**:
- The reason states that "Gold and platinum are expensive metals."
- This implies that their rarity and the difficulty of extraction contribute to their high cost.

4. **Evaluate the Reason**:
- Gold and platinum are indeed expensive due to their rarity and the fact that they do not corrode easily, making them desirable for various applications, including jewelry and electronics.
- **Conclusion**: The reason is also **correct**.

5. **Determine the Relationship**:
- Although both the assertion and the reason are correct, the reason does not explain why gold and platinum occur in native state. The occurrence in native state is due to their inertness and resistance to corrosion, not merely because they are expensive.
- **Conclusion**: The reason is not the correct explanation for the assertion.

6. **Final Answer**:
- Both the assertion and reason are true, but the reason is not the correct explanation of the assertion. Therefore, the correct option is:
- "Both assertion and reason are true, but reason is not the correct explanation of assertion."