Assertion : A force act upon the earth revolving in a circular orbit about the sun. Hence work should be done on the earth. Reason : The necessary centripetal force for circular motion of earth comes from the gravitational force between earth and sun.

• 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.