On what basis is the classification of ligands done?

Ethylene diaminetetraacetate $(EDTA^{4-})$ ion is:

$A$ complex compound of $Co^{3+}$ with molecular formula $CoCl_{x} \cdot yNH_3$ gives a total of $3$ ions when dissolved in water. How many $Cl^{-}$ ions satisfy both primary and secondary valencies in this complex?

Which among the following coordination compounds does not have a coordination number equal to the number of ligands?

The number of ligands which are directly bonded to the metal is known as

Which one of the following is an ambidentate ligand?