Which among the following ligands has the highest field strength?

Among the following pairs of complexes,in which case is the $\Delta_0$ value higher for the first one?

Match the electronic configurations in List-$I$ with appropriate metal complex ions in List-$II$ and choose the correct option.
[Atomic Number: $Fe=26, Mn=25, Co=27$]

List-$I$	List-$II$
$P$. $t_{2g}^6 e_g^0$	$1$. $[Fe(H_2O)_6]^{2+}$
$Q$. $t_{2g}^3 e_g^2$	$2$. $[Mn(H_2O)_6]^{2+}$
$R$. $e^2 t_2^3$	$3$. $[Co(NH_3)_6]^{3+}$
$S$. $t_{2g}^4 e_g^2$	$4$. $[FeCl_4]^{-}$
	$5$. $[CoCl_4]^{2-}$

On the basis of crystal field theory,explain why $Co(III)$ forms a paramagnetic octahedral complex with weak field ligands,whereas it forms a diamagnetic octahedral complex with strong field ligands.

The energies of $d_{xy}$ and $d_{z^2}$-orbitals in octahedral and tetrahedral transition metal complexes are such that

The electronic configuration of a metal ion in its complex is $[Ar] 3d^4$. For this metal complex,$\Delta_o < P$ ($P=$ energy required for electron pairing in a single orbital). The distribution of electrons in the complex is: