Yes, you are correct. The empire that overthrew the Byzantine Empire and effectively changed the region's religion to Islam is the Ottoman Empire, option C. The Ottoman Empire was a powerful and influential empire that emerged in the late 13th century and eventually conquered Constantinople (the capital of the Byzantine Empire) in 1453. After capturing Constantinople, the Ottoman Empire expanded its territories throughout the Eastern Mediterranean, Balkans, and parts of Eastern Europe. With their conquests, the Ottomans brought Islam as the dominant religion in the region, while the Byzantine Empire, which upheld Christianity, came to an end.
