Answer:
B) Their cavalry, fighting from horseback, unlike the Chinese who were not as well trained.
Explanation:
Mongols were not more united, nor did they have more equality than surrounding nations. Equality and unity depended on which clan they were in. Most Mongols did have writing, though them having literature to be added in the Middle Ages is debatable. However, the Chinese were very much literate, having one of the most complex languages in terms of the number of characters. Also, Mongols did care about religion somewhat, as they worshiped things like fire and earth, so they did have religion. However, their biggest advantage was their cavalry, which was well trained and superior to the Chinese cavalry.