Assertion: A current `I` flows I flows along the length of an infinitely long straght and thin walled pipe. Then the magnetic field at any point inside the pipe is zero.
Reason: `oint vec(B).d vec(l) =mu I`
A. If both the assertion and reason are true and reason is a true explantion of the assertion.
B. If both the assertion and reason are true but the reason is not the correct explantion of the assertion.
C. If the assertion is true but reason false
D. If both the assertion and reason are false.
