The correct answer is D. Constantinople
Step-by-step explanation
Eastern Roman Empire also was known as Byzantine Empire (since the year 395 to 1453) was a European empire which in its moment of greatest expansion occupied the territory of current Greece, Italy, Egypt, Turkish, Syria, Switzerland, Tunisia, South of Spain and north of Algeria. Its capital city was Constantinople, current Istanbul. Additionally, its form of government was the autocracy and its religion was Christianism.