Which of these statements about $[Co(CN)_6]^{3-}$ is true?

An aqueous solution of metal ion $M1$ reacts separately with reagents $Q$ and $R$ in excess to give tetrahedral and square planar complexes,respectively. An aqueous solution of another metal ion $M2$ always forms tetrahedral complexes with these reagents. Aqueous solution of $M2$ on reaction with reagent $S$ gives a white precipitate which dissolves in excess of $S$. The reactions are summarized in the scheme given below:
$1.$ $M1$,$Q$ and $R$,respectively are :
$(A)$ $Zn^{2+}, KCN$ and $HCl$
$(B)$ $Ni^{2+}, HCl$ and $KCN$
$(C)$ $Cd^{2+}, KCN$ and $HCl$
$(D)$ $Co^{2+}, HCl$ and $KCN$
$2.$ Reagent $S$ is :
$(A)$ $K_4[Fe(CN)_6]$
$(B)$ $Na_2HPO_4$
$(C)$ $K_2CrO_4$
$(D)$ $KOH$
Give the answer for question $1$ and $2$.

What is the shape and magnetic nature of the permanganate ion $(MnO_4^-)$?

Which of the following has a square planar geometry?
(At. nos.: $Fe=26, Co=27, Ni=28, Pt=78$)

The geometry of $[Ni(CO)_4]$ and $[NiCl_2(PPh_3)_2]$ are

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