A wire carrying current i is shaped as shown. Section AB is a quarter circle of radius r and current is flowing from A to B. The magnetic field is directed

• A

  At an angle $\pi /4$ to the plane of the paper

• B

  Perpendicular to the plane of the paper and directed into the paper

• C

  Along the bisector of the angle A CB towards AB

• D

  Along the bisector of the angle A CB away from AB