Assertion : A hollow metallic closed container maintained at a uniform temperature can act as a source of black body radiation. Reason : All metals acts as a black body [AIIMS 1996]

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