According to this rule, we first look at one face of the coil and if the current through the coil seems to be flowing in the clockwise direction, then that face is considered as the South pole. And if the current seems to be flowing in the anti-clockwise direction, then the face of the coil is considered as the North pole.

a) For this face of the coil, the current is flowing in the clockwise direction, so it acts as South-Pole.

b) For this face of the coil, he current if flowing in he anti-clockwise direction, so it acts as North-Pole.