Answer
Option b.
Current cw; north pole on bottom.
Work Step by Step
Using the right hand-curl method with our thumb pointing downwards, we see that our fingers curl in the clockwise direction.
As for the polarity of the current loop, we know that magnetic field lines point away from North poles and towards South poles on the outside of a bar magnet. Magnetic field lines are also always continuous. On the bottom part of the loop, where it appears as if the magnetic field lines go off into the ground, they actually will loop around and connect back at the top of the loop meaning the bottom of the loop is the north pole and the top of the loop is the south pole.
Option b. is correct.
