Answer
See explanation.
Work Step by Step
In a straight, finite solenoid, the magnetic field is approximately uniform inside, having the same magnitude and pointing along the axis. However, since the magnetic field lines form closed loops, the field lines must eventually emerge from one end to “come around” and join up with lines from the other end, so there is a field outside.
If the solenoid is bent around to form a torus (donut), in an ideal situation, it is reasonable for the entire magnetic field to be restricted to the interior volume.
