Which of the following complexes is diamagnetic and tetrahedral?

Magnetic moment (spin only) of an octahedral complex having $CFSE = -0.8 \Delta_0$ and surrounded by weak field ligands can be

$A$ mixture $X$ containing $0.02 \, mol$ of $[Co(NH_3)_5SO_4]Br$ and $0.02 \, mol$ of $[Co(NH_3)_5Br]SO_4$ is dissolved in water to make a $2 \, L$ solution.
$1 \, L \, of \, X + \text{Excess of } AgNO_3 \rightarrow Y \, mol \, of \, ppt.$
$1 \, L \, of \, X + \text{Excess of } BaCl_2 \rightarrow Z \, mol \, of \, ppt.$
Then $Y$ and $Z$ are respectively ...............

The configurations for the complex $[Co(en)(NH_3)_2Br_2]^+$ are shown. Which of the following statements is incorrect?

Among the statements $(a)-(d)$,the incorrect ones are:
$(a)$ Octahedral $Co(III)$ complexes with strong field ligands have very high magnetic moments.
$(b)$ When $\Delta_{0} < P$,the $d-$electron configuration of $Co(III)$ in an octahedral complex is $t_{2g}^{4} e_{g}^{2}$.
$(c)$ Wavelength of light absorbed by $[Co(en)_{3}]^{3+}$ is lower than that of $[CoF_{6}]^{3-}$.
$(d)$ If the $\Delta_{0}$ for an octahedral complex of $Co(III)$ is $18,000 \ cm^{-1}$,the $\Delta_{t}$ for its tetrahedral complex with the same ligand will be $16,000 \ cm^{-1}$.

Which will give $Fe^{3+}$ ions in solution?