A Very Long, Solid, Conducting Cylinder of Radius R Carries

Multiple Choice

A very long, solid, conducting cylinder of radius R carries a current along its length uniformly distributed throughout the cylinder. Which one of the graphs shown in the figure most accurately describes the magnitude B of the magnetic field produced by this current as a function of the distance r from the central axis?

A) 1
B) 2
C) 3
D) 4
E) 5