Aluminium chloride in acidified aqueous solution forms an ion having which geometry?

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:

The complex ion $[Co(C_2O_4)_3]^{3-}$ has which of the following hybridizations?

The hybridization observed in the $[PtCl_6]^{2-}$ ion is .......

Which of the following complexes formed by $Nickel$ is tetrahedral and paramagnetic?

Nickel $(Z = 28)$ combines with a uninegative monodentate ligand to form a diamagnetic complex $[NiL_4]^{2-}$. The hybridisation involved and the number of unpaired electrons present in the complex are respectively