The Magnitude of the Magnetic Field at Point P, at the Center

The magnitude of the magnetic field at point P, at the center of the semicircle shown, is given by:

A) 2 $\mu$ _0i/R²
B) $\mu$ ₀i/2 $\pi$ R
C) $\mu$ ₀i/4 $\pi$ R
D) $\mu$ ₀i/2R
E) $\mu$ ₀i/4R