Two wires AO and OC carry equal currents i as shown in figure. One end of both the wires extends to infinity. Angle AOC is\[\alpha \]. The magnitude of magnetic field at point P on the bisector of these two wires at a distance r from point O is

• A. \[\frac{{{\mu }_{0}}}{2\pi }\frac{i}{r}\cot \left( \frac{\alpha }{2} \right)\]
• B. \[\frac{{{\mu }_{0}}}{4\pi }\frac{i}{r}\cot \left( \frac{\alpha }{2} \right)\]
• C. \[\frac{{{\mu }_{0}}}{4\pi }\frac{i}{r}\frac{\left( 1+\cos \frac{\alpha }{2} \right)}{\sin \left( \frac{\alpha }{2} \right)}\]
• D. \[\frac{{{\mu }_{0}}}{4\pi }\frac{i}{r}\left( \frac{\alpha }{2} \right)\]