Answer:
C. Bosporus Strait.
Step-by-step explanation:
The capital city of the Byzantine Empire was "Constantinople." Constantinople is now known as "Istanbul," the capital city of Turkey.
Old Constantinople was located on the coast of the "Bosporus Strait" or the "Istanbul Strait." This strait links the Black Sea and the Sea of Marmara. It had a strategic location in terms of business and war. It allowed easy trading between Asia and Europe.