Which of the following complexes has the highest $C-O$ bond length?

Choose the correct statements from the following:
$A$. Ethane$-1, 2-$diamine is a chelating ligand.
$B$. Metallic aluminium is produced by electrolysis of aluminium oxide in the presence of cryolite.
$C$. Cyanide ion is used as a ligand for the leaching of silver.
$D$. Phosphine acts as a ligand in Wilkinson's catalyst.
$E$. The stability constants of $Ca^{2+}$ and $Mg^{2+}$ are similar with $EDTA$ complexes.
Choose the correct answer from the options given below:

Dimethyl glyoxime forms a coloured complex with

Assign $A, B, C, D$ from the given type of reaction: $AgI \downarrow + 2Na_2S_2O_3 \longrightarrow Na_3[Ag(S_2O_3)_2] + NaI$

Identify the ligand with the lowest field strength among the following.

Aqueous ammonia readily dissolves $AgCl$ because