The result of the Great Schism, which formally occurred in 1054, was primarily the division between the Roman Catholic Church in the West and the Eastern Orthodox Church in the East. Among the options listed, the most accurate result would be:
C. Formation of Protestantism
However, it's important to clarify that the Great Schism itself did not directly lead to the formation of Protestantism, which arose later in the 16th century during the Reformation. If you are specifically looking for the direct outcome of the Great Schism, none of the options precisely reflect that. The correct context should highlight the division into Roman Catholicism and Eastern Orthodoxy.
If you must choose one from the given options while considering broader historical implications:
D. Dominance of Eastern Orthodoxy in Eastern Europe could also be a valid consideration, as the division reinforced the spread and consolidation of Eastern Orthodoxy in that region.