Number of stereoisomers exhibited by $[Co(en)_{2} Cl_{2}]^{+}$ is

The total number of possible isomers for the complex compound $[Cu^{II}(NH_3)_4][Pt^{II}Cl_4]$ are

For an octahedral complex $MX_{4}Y_{2}$ ($M=$ a transition metal,$X$ and $Y$ are monodentate achiral ligands),the correct statement among the following is

The type of isomerism present in pentaammine nitro chromium$(III)$ chloride is

The electronic configurations of $Cr^{2+}, Mn^{2+}, Fe^{2+},$ and $Co^{2+}$ are $d^4, d^5, d^6,$ and $d^7$ respectively. Which of the following has the lowest magnetic moment? $[Cr = 24, Mn = 25, Fe = 26, Co = 27]$

Identify the diamagnetic octahedral complex ions from below $:$
$A. [Mn(CN)_6]^{3-}$
$B. [Co(NH_3)_6]^{3+}$
$C. [Fe(CN)_6]^{4-}$
$D. [Co(H_2O)_3F_3]$
Choose the correct answer from the options given below $:$