Reaction of $[Co(H_2O)_6]^{2+}$ with excess ammonia and in the presence of oxygen results into a diamagnetic product. Number of electrons present in $t_{2g}$-orbitals of the product is $.....$ .

The pair$(s)$ of complexes wherein both exhibit tetrahedral geometry is(are):
Note: $py = \text{pyridine}$
Given: Atomic numbers of $Fe, Co, Ni$ and $Cu$ are $26, 27, 28$ and $29$,respectively.
$(A)$ $[FeCl_4]^-$ and $[Fe(CO)_4]^{2-}$
$(B)$ $[Co(CO)_4]^-$ and $[CoCl_4]^{2-}$
$(C)$ $[Ni(CO)_4]$ and $[Ni(CN)_4]^{2-}$
$(D)$ $[Cu(py)_4]^+$ and $[Cu(CN)_4]^{3-}$

Identify the type of hybridization present in $[Ni(CN)_4]^{2-}$.

Which of the following statements are true about $[CoF_6]^{3-}$ ion?
$I$. The complex has octahedral geometry.
$II$. Coordination number of $Co$ is $3$ and oxidation state is $+6$.
$III$. The complex is $sp^3d^2$ hybridised.
$IV$. It is a high spin complex.

Match List-$I$ with List-$II$:

List-$I$ (Tetrahedral Complex)	List-$II$ (Electronic configuration)
$A$. $TiCl_4$	$I$. $e^2, t_2^0$
$B$. $[FeO_4]^{2-}$	$II$. $e^4, t_2^3$
$C$. $[FeCl_4]^{-}$	$III$. $e^0, t_2^0$
$D$. $[CoCl_4]^{2-}$	$IV$. $e^2, t_2^3$

Choose the correct answer from the options given below:

Among the following,the species that is both tetrahedral and diamagnetic is: