The hybridization involved in the complex $[Ni(CN)_4]^{2-}$ is (Atomic number of $Ni = 28$):

Addition of excess aqueous ammonia to a pink coloured aqueous solution of $MCl_2 \cdot 6H_2O (X)$ and $NH_4Cl$ gives an octahedral complex $Y$ in the presence of air. In aqueous solution,complex $Y$ behaves as a $1:3$ electrolyte. The reaction of $X$ with excess $HCl$ at room temperature results in the formation of a blue coloured complex $Z$. The calculated spin-only magnetic moment of $X$ and $Z$ is $3.87 \ B.M.$,whereas it is zero for complex $Y$.
Among the following options,which statement$(s)$ is(are) correct?
$[A]$ The hybridization of the central metal ion in $Y$ is $d^2sp^3$
$[B]$ $Z$ is a tetrahedral complex
$[C]$ Addition of silver nitrate to $Y$ gives only two equivalents of silver chloride
$[D]$ When $X$ and $Z$ are in equilibrium at $0^{\circ}C$,the colour of the solution is pink

In which of the following complex ions is the central metal atom's $d$-orbital devoid of electrons?

Which of the following statements is correct?

Which of the following complexes exhibits a square planar geometry?

The hybridised orbitals used by silver in the complex $[Ag(NH_3)_2]^+$ are of the type