Combination of the top two options depending on how often the same person feeds them - though provided there is no backlash from the human community (ie negative events happening to the ducks like duckkicking) they will silmply lump humans one and all into the category of harmless.
If they do get negative events occuring chances are they will be in group 4 - food being too tempting ot resist, but aware that humans are a threat - at which point they will widen their range toward people when on land - on water they tend to be more confident