assertion(a): spring balances show incorrect readings after using for a long time.

reason(r): on using for a long time, springs in the balances lose their elastic strength.

A. both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. both Assertion & Reason are True but Reason is not a correct explanation of the Assertion.
C. Assertion is True but the Reason is False.
D. both Assertion & Reason are false.