Assertion: A black body is an ideal body that emits and absorbs radiation of all frequencies.

Reason: The frequency of radiation emitted by a body goes from lower frequency to a higher frequency with an increase in temperature.

1.  Both the assertion and the reason are true and the reason is the correct explanation of assertion.

2.  Both the assertion and the reason are true and the reason is not the correct explanation of assertion.

3.  The assertion is true but the reason is false.

4.  The assertion is false but the reason is true.