I believe the answer is c.
The last one. During the crusades, different foods and such were found, different goods were unlocked to europe, and different mathematic and scientific ideas were brought back as well.
Well the exact translation of Islam is submission. So the belief in the existence of the Islamic god Allah, as well as angels. Belief that the Quran is legitamite. Then there's other stuuf like the Gospel (showed to Jesus), the Torah (Moses), then finally Psalms (David). Bascially saying like submit yourself to Allah and what not.
<span>The basic beliefs of Jesus that are preached are based on monotheism of Judaism, and generally reject Hellenistic and Roman influence. Though the Romans tried to stop it, Christianity spread like wild fire through missionaries and merchants in afro-eurasia and finally began to get backing from Romans under Constantine.</span>
