Which of the following is a low spin complex?

Match List-$I$ with List-$II$ and select the correct option:

List-$I$	List-$II$
$(A). [Ag(CN)_2]^-$	$1. \text{Square planar, } 1.73 \, B.M.$
$(B). [Cu(CN)_4]^{3-}$	$2. \text{Linear, } 0 \, B.M.$
$(C). [Cu(CN)_6]^{4-}$	$3. \text{Octahedral, } 0 \, B.M.$
$(D). [Cu(NH_3)_4]^{2+}$	$4. \text{Tetrahedral, } 0 \, B.M.$
$(E). [Fe(CN)_6]^{4-}$	$5. \text{Octahedral, } 1.73 \, B.M.$

List-$I$ contains metal species and List-$II$ contains their properties.

List-$I$	List-$II$
$I$. $[Cr(CN)_6]^{4-}$	$P$. $t_{2g}$ orbitals contain $4$ electrons
$II$. $[RuCl_6]^{2-}$	$Q$. $\mu$ (spin-only) $= 4.9 \ BM$
$III$. $[Cr(H_2O)_6]^{2+}$	$R$. low spin complex ion
$IV$. $[Fe(H_2O)_6]^{2+}$	$S$. metal ion in $4+$ oxidation state
	$T$. $d^4$ species

[Given: Atomic number of $Cr = 24, Ru = 44, Fe = 26$] Match each metal species in List-$I$ with their properties in List-$II$,and choose the correct option.

Three arrangements are shown for the complex $[CoBr_2(NH_3)_2(en)]^{\oplus}$. Which one is the wrong statement?

$0.001 \ mol$ of $Co(NH_3)_5(NO_3)(SO_4)$ was passed through a cation exchanger. The acid coming out of it required $20 \ mL$ of $0.1 \ M$ $NaOH$ for neutralization. Hence,the complex is:

For the reaction $K_4[Fe(CN)_6] \xrightarrow{\text{oxidation}} Fe^{3+} + CO_2 + NO_3^-$,which of the following statements is incorrect?