Magnetic moment of $d^6$ low spin complex is ........ $B.M.$

$STATEMENT-1$: The geometrical isomers of the complex $[M(NH_3)_4Cl_2]$ are optically inactive.
$STATEMENT-2$: Both geometrical isomers of the complex $[M(NH_3)_4Cl_2]$ possess a plane of symmetry.

The spin-only magnetic moment of $[Mn(H_2O)_6]^{2+}$ complex is $........ \ B.M.$ (Nearest integer) (Given: Atomic number of $Mn$ is $25$)

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

An aqueous solution of $[Ni(H_2O)_6]^{2+}$ contains $Ni^{2+}$ ions and has a magnetic moment of $2.83 \ BM$. What is the effect on the magnetic moment of the solution when ammonia is added?

The $d-$electron configurations of $Cr^{2+}, Mn^{2+}, Fe^{2+}$ and $Co^{2+}$ are $d^4, d^5, d^6$ and $d^7$ respectively. Which one of the following will exhibit minimum paramagnetic behaviour?
(At. nos. $Cr = 24, Mn = 25, Fe = 26, Co = 27$)