Both $[Ni(CO)_4]$ and $[Ni(CN)_4]^{2-}$ are diamagnetic.The hybridisation of nickel in these complexes ,respectively are

Question

$\begin{array}{1 1}(a)\;sp^3,sp^3&(b)\; sp^3,dsp^2\\(c)\;dsp^2,sp^3&(d)\;dsp^2,dsp^2\end{array}$