A long straight cylindrical shell has an inner radius Ri and an outer radius Ro. It carries a current I, uniformly distributed over its cross section. A wire is parallel to the cylinder axis, in the hollow region (r Ro). 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. Please explain why.