What is the number of $=N-OH$ groups present in dimethyl glyoximato?

Homoleptic complexes among the following are:
$(A)$ $K_3[Al(C_2O_4)_3]$
$(B)$ $[CoCl_2(en)_2]^{+}$
$(C)$ $K_2[Zn(OH)_4]$

$A$ $200 \ mL$ solution $X$ contains $0.02 \ mol$ of $[Co(NH_3)_5Br]Cl_2$ and $0.02 \ mol$ of $[Co(NH_3)_5Cl]SO_4$. If solution $X$ is treated with excess $AgNO_3$ and excess $BaCl_2$,what will be the number of moles of precipitates $Y$ and $Z$ formed,respectively?

Which compound is a zero-valent metal complex?

What is the number of donor atoms in dimethylglyoximato ligand?

The coordination number of copper in cuprammonium sulfate is.....