Which of the following is paramagnetic?

$\mathrm{Fe}^{2+}$ electronic configuration is $[\mathrm{Ar}] 3 \mathrm{ d}^{6}$. Since CN is strong field ligand d electrons are paired. In $\mathrm{Ni}(\mathrm{CO})_{4} \mathrm{O}. \mathrm{S}$. of $\mathrm{Ni}$ is zero electronic configuration is $[\mathrm{Ar}\} 3 \mathrm{ d}^{8} 4 \mathrm{ s}^{2}. \mathrm{In}$ presence of $\mathrm{CO}$ it is $[\mathrm{Ar}] 3 \mathrm{ d}^{10} 4 \mathrm{ s}^{0},$ electrons are paired. Electronic configuration of $\mathrm{Ni}^{2+}[\mathrm{Ar}] 3 \mathrm{ d}^{8} 4 \mathrm{ s}^{0},$ due to $\mathrm{CN}^{-}$ ligand all electrons are paired. $\mathrm{Co}^{3+}$ is $[\mathrm{Ar}] 3 \mathrm{ d}^{6}$ since $\mathrm{F}$ is weak ligand hence paramagnetic.