Concept:A neutral ligand is a molecule or ion that coordinates to a metal center without carrying any net charge.Explanation:The nitrato ligand is NO3−​, which has a negative charge.The cyano ligand is CN−, which also has a negative charge.The iodo ligand is I−, which is negatively charged.The aqua ligand is H2​O, which has no net charge.Hence, among the given options, aqua is the neutral ligand.Answer:Option C – Aqua.