The total number of possible isomers for $[Cu^{II}(NH_3)_4] [Pt^{II}Cl_4]$ is..........

The metal ions that have the calculated spin-only magnetic moment value of $4.9 \ B.M.$ are:
$A. Cr^{2+}$ $B. Fe^{2+}$ $C. Fe^{3+}$ $D. Co^{2+}$ $E. Mn^{3+}$
Choose the correct answer from the options given below:

Select the correct statement about $[Mn(CO)_4NO]$ which is diamagnetic.

Which of the following complex ions is not diamagnetic?

The spin-only magnetic moment value of $M^{n+}$ ion formed among $Ni$, $Zn$, $Mn$, and $Cu$ that has the least enthalpy of atomisation is $........$ (in nearest integer). Here $n$ is equal to the number of diamagnetic complexes among $K_2[NiCl_4]$, $[Zn(H_2O)_6]Cl_2$, $K_3[Mn(CN)_6]$, and $[Cu(PPh_3)_3I]$.

Which of the following compounds will show optical isomerism?