Assertion: ZnO becomes yellow when it is heated. Reason : Metal excess defect arises due to excess of Zn ²⁺ ions which move to interstitial sites and the electron moves to neighbouring interstitial sites.

Options

1. AIf both assertion and reason are true and reason is the correct explanation of assertion.
2. BIf both assertion and reason are true but reason is not the correct explanation of assertion.
3. CIf assertion is true but reason is false.
4. DIf both assertion and reason are false.