17.In figure, the upper wire has two straight lines and a semicircular arc of radius 4.0 cm. The lower wire is parallel to the upper wire and separated by 10 cm. The upper wire carries a current of 10 A and the lower wire carries the return current. The magnitude of the magnetic field at the center of the semicircular arc P, in μT, is closest to: (A) 80 (B) 60 (C) 100 (D) 140 (E) 180