which best explains why constantinople did not fall until 1453?\nthe city was well protected and repelled…

which best explains why constantinople did not fall until 1453?\nthe city was well protected and repelled attacks by invaders.\nthe city created alliances with europeans to stop most attacks.\nthe city was far from byzantine territories and only attacked once.\nthe city created alliances with invaders to stop most attacks.
Answer
Answer:
The city was well protected and repelled attacks by invaders.
Brief Explanations:
Constantinople had strong fortifications like the Theodosian Walls which helped it resist numerous invasions over the centuries until the powerful siege in 1453.