assertion : when current is passed through a helical spring its natural length decreases.

reason : when current is passed through a helical spring its time period increases

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.