Of the following complex ions, which is diamagnetic in nature?

Electronic configuration of $\mathrm{Ni}^{2+}$ in \left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$<img src="https://cdn-question-pool.Quantrex.app/pyq/neet/BvlCRzhnAOgiuAzhDkPNBpUAF7pZoxk82Q77gIjUvrc.original.fullsize.png"><br>$\mathrm{Ni}^{2+}$has$d s p^2$hybridisation, as$\mathrm{CN}^{-}$is a strong field ligand.<img src="https://cdn-question-pool.Quantrex.app/pyq/neet/NaF8c0LTZztyyluFowWKaNsC99aGvtMUJldu5I0u_1Q.original.fullsize.png"><br>$\therefore\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-} is diamagnetic (becasue of the absence of unpaired electrons).