The correct answer is - C. Region A.
The Ottoman Empire was a very large empire, and it was spread out on three continents, Europe, Asia, and Africa. The basis of this empire was Anatolia, in present day Turkey, which is marked with the letter A on the map. From Anatolia, the Ottomans managed to conquer most of the Balkan Peninsula, large portion of the Middle East and Caucasus regions, as well as the coastal areas of North Africa. The territory that this empire managed to gain under its control made it a major player in the world, as it had everything from natural resources, to excellent strategic position, large population, big production of various products etc.