Which of the following complexes is an outer orbital complex?

Cobalt chloride when dissolved in water forms a pink-colored complex $X$ which has an octahedral geometry. This solution,upon treatment with concentrated $HCl$,forms a deep blue complex $Y$ which has a $Z$ geometry. $X$,$Y$,and $Z$,respectively,are:

Match List-$I$ with List-$II$.

List-$I$	List-$II$
$A$. $[MnBr_4]^{2-}$	$I$. $d^2sp^3$ and diamagnetic
$B$. $[FeF_6]^{3-}$	$II$. $sp^3d^2$ and paramagnetic
$C$. $[Co(C_2O_4)_3]^{3-}$	$III$. $sp^3$ and diamagnetic
$D$. $[Ni(CO)_4]$	$IV$. $sp^3$ and paramagnetic

Choose the correct answer from the options given below:

Match List-$I$ with List-$II$.

List-$I$	List-$II$
$A. Ni(CO)_4$	$I. sp^3$
$B. [Ni(CN)_4]^{2-}$	$II. sp^3d^2$
$C. [Co(CN)_6]^{3-}$	$III. d^2sp^3$
$D. [CoF_6]^{3-}$	$IV. dsp^2$

Choose the correct answer from the options given below.

The number of unpaired electrons in $Ni(CO)_4$ is ..........

In the complex $cis-[Cr(en)_2Cl_2]^+$,the oxidation state of $Cr$,the type of $d$-orbital involved in the valence shell,and the coordination number are respectively: