AIPMT 2014 Physics and Chemistry Paper

Two identical long conducting wires AOB and COD are placed at right angle to each other, with one above other such that ' O ' is their common point for the two. The wires carry I1 and I2 currents respectively. Point ' P ' is lying at distance ' d ' from ' O ' along a direction perpendicular to the plane containing the wires. The magnetic field at the point ' P ' will be :-