Current \( I \) flows through a long conducting wire bent at right ...

Current \( I \) flows through a long conducting wire bent at right angles as shown in the Fig. 4(CF).3. The magnetic field at a point \( P \) and the right bisector of the angle \( C O D \) at a distance \( r \) from \( O \) is
(a) \( \frac{\mu_{0} I}{\pi r} \)
(b) \( \frac{2 \mu_{0} I}{\pi r} \)
(c) \( \frac{\mu_{0} I}{4 \pi r}(\sqrt{2}+1) \)
(d) \( \frac{\mu_{0}}{4 \pi} \frac{2 I}{r}(\sqrt{2}+1) \)