Assertion: Radian is the unit of distance. Reason: One radian is the angle subtended at the centre of a circle by an arc equal in length to the radius of the circle.

• 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.