A long straight cylindrical shell has inner radius Ri and outer radius Ro. It carries current i, uniformly distributed over its cross section. A wire is parallel to the cylinder axis, in the hollow region (rRo). We conclude that the wire:
A. is on the cylinder axis and carries current i in the same direction as the current in the shell
B. may be anywhere in the hollow region but must be carrying current i in the direction opposite to that of the current in the shell
C. may be anywhere in the hollow region but must be carrying current i in the same direction as the current in the shell
D. is on the cylinder axis and carries current i in the direction opposite to that of the current in the shell
E. does not carry any current
