The highest value of the calculated spin-only magnetic moment (in $BM$) among all the transition metal complexes is

$[Co(NH_3)_5SO_4]Br$ and $[Co(NH_3)_5Br]SO_4$ are a pair of isomers.

Total number of cis $N-Mn-Cl$ bond angles (that is,$Mn-N$ and $Mn-Cl$ bonds in cis positions) present in $cis-[Mn(en)_2Cl_2]$ is: $(en = NH_2CH_2CH_2NH_2)$

The correct order of the number of unpaired electrons in the given complexes is
$A$. $[Fe(CN)_6]^{3-}$; $B$. $[FeF_6]^{3-}$; $C$. $[CoF_6]^{3-}$; $D$. $[Cr(oxalate)_3]^{3-}$; $E$. $[Ni(CO)_4]$
Choose the correct answer from the options given below:

What is the spin-only magnetic moment of an element having one unpaired electron (in $BM$)?

Which of the following is not a coordination isomer of $[Cr(NH_3)_6][CoCl_6]$?