The Principality of Muscovy (Moscow)eventually Emerged as the Most Powerful

The principality of Muscovy (Moscow) eventually emerged as the most powerful principality of the Rus principalities because

A) Kiev became the center of the Qipchaq khanate.
B) Moscow continued as the Eastern Orthodox center.
C) Ivan III led a force that brought the Qipchaq khanate to an end.
D) the forces of Kiev were unable to defeat the Rus-Mongol armies for the control of the region.
E) Ivan III joined with the forces of the Il-khanate to oust the Qipchaq khanate.