Galicia is quite mountainous, a fact which has contributed to isolate the rural areas, hampering communications, most notably in the inland. The main mountain range is the Macizo Galaico (Serra do Eixe, Serra da Lastra, Serra do Courel), also known as Macizo Galaico-Leones, located in the eastern parts, bordering with Castile and Leon. Noteworthy mountain ranges are O Xistral (northern Lugo), the Serra dos Ancares (on the border with Leon and Asturias), O Courel (on the border with Leon), O Eixe (the border between Ourense and Zamora), Serra de Queixa (in the center of Ourense province), O Faro (the border between Lugo and Pontevedra), Cova da Serpe (border of Lugo and A Coruna), Montemaior (A Coruna), Montes do Testeiro, Serra do Suido, and Faro de Avion (between Pontevedra and Ourense); and, to the south, A Peneda, O Xures and O Larouco, all on the border of Ourense and Portugal.
Try to answer this question if possible (otherwise reply "unanswerable"): Its southern mountain ranges are on the border with which country?
Portugal