Ligands can form dative covalent bonds with metal ions to form complex ions. Which of the following can act as a ligand?

I.     ${\text{C}}{{\text{l}}^ - }$

II.     ${\text{N}}{{\text{H}}_{\text{3}}}$

III.     ${{\text{H}}_{\text{2}}}{\text{O}}$

A.     I and II only

B.     I and III only

C.     II and III only

D.     I, II and III

D