Assertion : The absorbance of a perfect black body is unity. Reason : A perfect black body when heated emits radiations of all possible wavelengths at that temperature.

• 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.