Test analysis: In the test, the magnetic induction lines inside and outside the bar magnet form a closed curve, so the total number of magnetic induction lines outside the magnet is equal to the total number of internal magnetic induction lines, and the magnetic induction lines inside and outside the magnet are in opposite directions. The magnetic induction lines outside the magnet are distributed in infinite space, so there are more magnetic induction lines inside the magnet in the circle in the figure than outside. Because of the opposite direction, the external magnetic induction lines should cancel some internal magnetic induction lines. When the spring area increases, the total number of internal magnetic induction lines remains unchanged. However, when the offset increases and the residual decreases, the magnetic flux will decrease. Therefore, when the spring area increases, the magnetic flux φ passing through the circuit decreases. In addition, the induction line in the bar magnet is from the S pole to the N pole, so Lenz's law shows that the induced current in the ring is counterclockwise (from top to bottom), so A is correct; BCD error;

So choose: a

Comments: In this question, the magnetic field passing through the coil has two directions, and the magnetic induction line is offset. We should compare the magnetic flux according to the residual magnetic induction line after migration. At the same time, it is necessary to investigate that the induction line inside the bar magnet is from S pole to N pole, and learn to use Lenz's law: increase and decrease the same.