"A firefighter in Wales."
Translation:Neach-smàlaidh anns a' Chuimrigh.
This sort of thing needs flagged, as the mods may not read this otherwise. One possible explanation: were you offered sa by any chance? This is valid, has no apostrophe, but has not yet been introduced. However, I complained when it wasn't permitted, so it is possible that it is now on the list of permissible answers and so Duo was expecting you to use it, even though it has not yet been taught.