Assertion: The ratio of intertial mass to gravitational mass is equal to one.
Reason: The inertial mass and gravitational mass of a body are equivalent.
A. If both assertion and reason are true and the reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true statement but reason is false.
D. If both assertion and reason are false.