Based on my information, your correct answer would actually be the very first option. When the city was actually well protected, they're still people that could still come in and repelled and attacks from the invaders. But this is what those other people have thought, they were not able to actually break in. They were so armed and protected as a small little city, they were not able to break in the city at any point. This would be the reason to why the Constantinople didn't fall until 1453. Your answer would then be the first option as it would read the following: "The city was well protected and repelled attacks by Invaders".
