What is the number of unpaired electrons in $[Co(NH_3)_6]^{3+}$ complex?

Which of the following is/are correct for the complex $[Cu(NH_3)_4]^{2+}$?

The number of isoelectronic species among $Sc^{3+}$, $Cr^{2+}$, $Mn^{3+}$, $Co^{3+}$, and $Fe^{3+}$ is $n$. If $n$ moles of $AgCl$ are formed during the reaction of the complex with the formula $CoCl_{3}(en)_{2}NH_{3}$ with excess $AgNO_{3}$, then the number of electrons present in the $t_{2g}$ orbital of the complex is . . . . . . .

Which among the following statements about $[Ni(CN)_4]^{2-}$ is $NOT$ true?

Among $[Ni(CO)_4]$,$[Ni(CN)_4]^{2-}$,and $[NiCl_4]^{2-}$ species,the hybridization states at the $Ni$ atom are,respectively:

Match the type of hybridization given in List-$I$ with the molecules/ions given in List-$II$.

List-$I$	List-$II$
$(1)$ $dsp^2$	$(A)$ $BrF_5$
$(2)$ $sp^3d^2$	$(B)$ $[Co(NH_3)_6]^{3+}$
$(3)$ $sp^3d$	$(C)$ $[PtCl_4]^{2-}$
$(4)$ $d^2sp^3$	$(D)$ $PCl_5$