One of your given translations is 'Maize'. Why is it marked as incorrect?
Use "report a problem," not "comment," when there is an error like this. It's happened to me in lessons in other languages too. The Duolingo people can't watch all the discussions, but I think they act pretty promptly when people report problems.
they totally call milho maize in most of sub-saharan africa in the english speaking countries -- so I'd say the correct mozambican or angolan translation of milho would be maize :)