Answer:
Correct answer is C. Christian beliefs spread throughout Europe.
Step-by-step explanation:
Option A is not correct as after this event authority of Pope grew stronger. Popes started losing their influence after the Crusades.
B is not correct as Jesus was crucified in the 1st Century and Christianity becomes the religion of the Roman Empire in the 4th Century.
C is correct as the Roman Empire was covering most of the Europe at the time and therefore allowed Christianity to spread across it.
D is not correct as Orthodox Church was created much later. Officially we can say after 1054 (Great Schism).