Answer: Bosporus Strait
Explanation: If you look at the map of the Byzantine Empire from the 1360 AC, you can see that the former vast Empire was reduced almost to the area around Constantinople. and that area from the European side. Constantinople itself is a city located on two continents to Europe and Asia, and the border between continents is Bosporus Strait that connects the Black Sea and the Sea of Marmara. So in the period of 1360 AC the only water body in the Byzantine Empire of the offered options is Bosporus Strait.
