Assertion (A): Sodium metal is stored under kerosene. Reason (R): Metallic sodium melts when exposed to air.

1. Assertion (A) states that Sodium metal is stored under kerosene. This is true because sodium is highly reactive with air (oxygen and moisture) and reacts vigorously with water. 2. Reason (R) states that Metallic sodium melts when exposed to air. This is false. Sodium reacts (oxidizes, tarnishes) rapidly when exposed to air, generating heat, but it does not simply melt due to air exposure at room temperature (its melting point is 97.8°C). 3. Since Assertion (A) is true and Reason (R) is false, option (C) is the correct answer.