What is the magnetic induction B at the centre O of the semicircular arc if a current carrying wire has shape of a hair pin as shown in figure? The radius of the curved part of the wire is $$R$$, the linear parts are assumed to be very long.

A

$$B = \frac{\mu_0 I}{4\pi R}(\pi + 2)$$

B

$$B = \frac{\mu_0 I}{4 R}(\pi + 2)$$

C

$$B = \frac{3\mu_0 I}{4 R}\pi + 2)$$

D

$$B = \frac{\mu_0 2I}{4\pi R}$$