Which of the following statements is correct regarding the $[Fe(CN)_6]^{4-}$ complex?

According to Valence Bond Theory,the number of unpaired electrons present in $[MnCl_6]^{3-}$,$[Fe(CN)_6]^{3-}$ and $[Co(C_2O_4)_3]^{3-}$,respectively,are

Explain the complex species $[Ni(CN)_4]^{2-}$ on the basis of Valence Bond Theory $(VBT)$.

Which of the following is/are correct for the complex $[Cu(NH_3)_4]^{2+}$?

The total number of unpaired electrons present in $[Co(NH_3)_6]Cl_2$ and $[Co(NH_3)_6]Cl_3$ is $......$

What is the type of hybridisation and the geometry respectively found in $[CoF_{6}]^{3-}$?