Assertion : A current `I` flows along the length of an infinitely long straight and thin walled pipe. Then the magnetic field at any point inside the pipe is zero.
Reason : `oint vecB.dvecl=mu_(0)I`
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.