I think the answer might be c
Answer:
The 1st one is the Volga River, 2nd Lake Baikal, 3rd Balitic sea and 4th Black sea
On May 29, 1453, after an Ottoman army stormed Constantinople, Mehmed triumphantly entered the Hagia Sophia, which would soon be converted to the city's leading mosque. ... Emperor Constantine XI died in battle that day, and the Byzantine Empire collapsed, ushering in the long reign of the Ottoman Empire.