A Long Straight Cylindrical Shell Has an Inner Radius R_i

Multiple Choice

A long straight cylindrical shell has an inner radius R_i and an outer radius R_o.It carries a current i, uniformly distributed over its cross section.A wire is parallel to the cylinder axis, in the hollow region (r < R_i) .The magnetic field is zero everywhere in the hollow region.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