Curl the palm of your right hand around the circular wire with the fingers pointing in the direction of current and the thumb gives the direction of the magnetic field. In this case the upper side of the loop may be thought of as:
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Use the right-hand rule to determine the direction of the magnetic field around a current-carrying conductor.
By using the right-hand rule, the thumb pointing in the direction of the magnetic field gives the north pole on the upper side of the loop.
Thus, the correct answer is option (4).