I believe c is the answer because the word it's is saying it is
America didn't trust the middle east anymore because that's where most of the terrorists are and they didn't want to take a chance with them attacking again
Based on the map I've attached, I'd say that Christianity spread to
most of the Roman Empire by 476 AD. If you look at the map, you will see that before 325, there were some places in Spain and Italy mostly where Christianity existed, however, after that year, it only continued spreading throughout Europe, which mostly belonged to the Roman Empire at the time.