Which of the following ligands possesses only one coordination site?

The coordination number of a central metal atom in a complex is determined by:

$2.33 \ g$ of compound $X$ (empirical formula $= CoH_{12}N_{4}Cl_{3}$) upon treatment with excess $AgNO_{3}$ solution produces $1.435 \ g$ of a white precipitate. The primary and secondary valences of cobalt in compound $X$,respectively are.
[Given,atomic mass : $Co = 59, Cl = 35.5, Ag = 108$]

What is the number of donor atoms in dimethylglyoximato ligand?

The bonds in ${K_4[Fe(CN)_6]}$ are

The primary and secondary valencies of cobalt respectively in $[Co(NH_3)_5Cl]Cl_2$ are :