Which of the following is diamagnetic ?

$\left[\mathrm{CoF}_{6}\right]^{3-}$

$\left[\mathrm{FeF}_{6}\right]^{3-}$

$\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}$

$\left[\mathrm{Co}(\mathrm{Ox})_{3}\right]^{3-}$