Moving Charges And Magnetism

A current carrying loop $A B C D$ has two circular arcs $A D$ and $B C$ with radius 1 cm and 2 cm respectively, as shown in the figure. The two arcs $A D$ and $B C$ subtend a common angle $30^{\circ}$ at the centre $O$. If the current flowing in the loop is $\frac{12}{\pi} \mathrm{~A}$. Then, the magnitude of net magnetic field at $O$ is (given, $\mu_0=4 \pi \times 10^{-7}$ )