$\left[Fe\right(H_{2}O{)}_{5}NO{]}^{2+}$ is a complex formed during the brown ring test for $N{O}_3^{-}$ ion. In this complex :

The correct option is B All of the above statements are correct
In brown ring complex, iron exists in $+1$ due to transfer of one electron from $NO$ and in $+1$ oxidation state iron has 3 unpaired electrons. The color of the complex is due to the charge transfer.