In the opposite figure, the total magnetic flux density at point (O) equals:
Knowing that \( \left(\mu_{\text {air }}=4 \pi \times 10^{-7} \mathrm{~Wb} /\right. \) Amp. \( \mathrm{m}, \pi=3.14 \) )
(A) \( 1.442 \times 10^{-5} \mathrm{~T} \)
(B) \( 5 \times 10^{-6} \mathrm{~T} \)
(C) \( 9.42 \times 10^{-5} \mathrm{~T} \)
(D) \( 4.42 \times 10^{-6} \mathrm{~T} \)