It is confusing. I thought it meant 'has territory in Africa, Europe, and Asia' so I guessed the UK but I guess if you don't consider Eurasia a continent then this is right.
Afghanistan flew a plain white flag for around 1 year under the Taliban. (it also once flew a black flag a long time ago, but back then it probably wasn't considered Afghanistan)
If you choose to change the question but still want something to do with a flag, you could change it to the only country that has a flag without the colors red, white, or blue: Jamaica.
Not certain but Nauru has traffic lights for when the main road crosses the taxiway at the airport; in Tuvalu this also happens so perhaps there's traffic lights there?
The Spanish coat of arms on the flag of Spain has a lion, but its colour is not entirely clear. I've looked at a few pictures, and sometimes it looks pinkish, sometimes it looks outright purple. Maybe worth checking out what colour it official is, just in case it might be meant to be purple!
Spain (Ceuta, Melilla, Canary Islands), Portugal (Madeira), and France (Mayotte, Reunion) are also in both Africa and Eurasia. If we count external territories, we would also have to add United Kingdom (St Helena, Ascension, and Tristan da Cunha). I think that question should be removed.
How does "Eurafrasian" apply to Egypt but not Spain? And isn't Afro-Eurasia a supercontinent composed of Africa, Europe, and Asia? If so, then any country on any of those three continents is properly categorized as Eurafrasian. A country on the continent of Europe is Europe. A country on the supercontinent of Afro-Eurasia is Eurafrasian. They would all satisfy that answer.
https://en.wikipedia.org/wiki/Flag_of_Afghanistan