Which of the complexes has the magnetic moment of 3.87 B.M.?

Options

1. A\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}
2. B\left[\mathrm{CoF}_6\right]^{3-}
3. C\left[\mathrm{CoCl}_4\right]^{2-}
4. D$\left[\mathrm{Co}(\mathrm{dmg})_2\right]$ square planar complex $(\mathrm{dmg}=$ dimethyl glyoxime $)$