For the coil in the diagram below, when the switch is pressed:
(a) what is the polarity of end A?
(b) which way will the compass point then?
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When the switch is pressed,

(a) the current will flow in the clockwise direction at end A, as it has a plus or positive end, therefore, this end will behave like the south pole.

(b) as end A behaves as the south pole, then the other or opposite end B, of the coil will behave like the north pole, and because of the repulsive force at the north pole, the compass (or point of the compass) will move away from the coil.

Extra information with the image is for reference only

The north-south polarities of an electromagnet can be found easily by using the Clock face rule, because according to this rule "when an observer, finds the direction of current flowing in the anti-clockwise direction at one face of the coil, then the face of the coil will behave like the North Pole. On the other hand, if the observer, finds the direction of current flowing in the clockwise direction, then the face of the coil will behave like the South Pole".