ELECTROMAGNETISM

(a) Since the current flows to the right, use the thumb to point in the direction of current, the other fingers give the direction of magnetic field lines.

Hence, the direction of file dlines at A is pointing out from the paper and at B is into the paper.
(b) Since the current is going into the paper, application of the right hand grip rule gives that the field line direction at A is vertically upward and at B is vertically downward.