What is the source of the magnetic field inside the box?

[yeo]

Question:
http://web.ics.purdue.edu/~yeo/phys1.jpg

Formula: (Gauss's Law for Magnetism)
Line integral of[B dot nhat(perpendicular unit vector) * deltaA] = 0

The Attempt at a Solution

So, if there is a bar magnet inside, the side arrows are pointing in the wrong direction, so I ruled that out.

A magnetic monopole will have all arrows emanating from the center or all pointing towards the center, so I ruled that out.

The total flux is not 0, so there has to be something in it?

->That left me with only 2 other choices, but I've tried all combinations of them and none of them are correct. Any help guys? I only have 2 more tries left and its due tomorrow...

Thanks a lot!

 

[rl.bhat]

The fourth choice is correct, because if you keep a current carrying coil inside it will also have the lines of magnetic fields entering and leaving.

 

[Dick]

The flux through the box is nonzero. You are right, there is 'something' inside it. If you believe the flux. But we know of no magnetic sources (i.e. monopoles). And a current carrying wire is NOT A SOURCE. It has div(B)=0. Conclusion?