Solution

Denticity of a ligand is the number of donor atoms through which it can link to a central metal atom or the number of coordinating groups present in a ligand is called the denticity of the ligand.

If a ligand has one binding atom it is called Monodentate. Example $$NH_3, H_2O, CO$$
If a ligand has two binding atoms it is called Bidentate. Example $$Ethylenediamine,Oxalate(C_2O_4^{2-})$$
If a ligand has three binding atoms it is called Tridentate. Example$$Diethylenetriamine$$
If a ligand has six binding atoms it is called Hexadentate. Example $$ethylenediaminetetraacetate$$

Ethylenediamine $$(NH_2-CH_2-CH_2-NH_2)$$ has two donor atom, it can bind with central metal atom through two nitrogen atom. Therefore it is a $$Bidentate$$ ligand.

Therefore, Ethylenediamine is not an example of monodentate, tridentate and hexadentate ligand.

Hence correct options are (A), (C) and (D).