39 Why does the author mention “Constantinople” in Paragraph 2?
(A) To imply that having a strong border gives people a sense that they can be more open.
(B)To make readers doubt the boast the city once made of having a formidable wall.
(C)To suggest that the world’s great center of commerce was the crossroads and the harbor.
(D)To question whether a walled city necessarily means closedness.