A coaxial cable consists of a long, solid cylindrical inner conductor of radius \(a\) and a thin cylindrical outer shell of radius \(b\). The inner conductor carries a uniformly distributed current \(I\) out of the page, and the outer shell carries an equal current \(I\) into the page. Which graph best represents the magnitude of the magnetic field \(B\) as a function of distance \(r\) from the central axis of the cable?