The correct answer is - a. Greece.
The country of Greece, located on the southern part of the Balkan Peninsula, is a country that is consisted from the mainland part and over two thousand islands on top of it. The islands very in size significantly, from medium sized, to extremely small ones. The islands surround the mainland from three sides, and they are dispersed in the Mediterranean Sea, the Aegean Sea, and the Ionian Sea. About big portion of the eastern islands there's territorial dispute with Turkey, as well as for few islands on the west where there's disputes with Albania.
