Can someone

which group invaded and conquered russia in the early thirteenth century?

a. mongols who leveled cities, looted treasures, and massacred entire populations
b. muslim armies who introduced islam and imported middle eastern art, science, and architecture
c. chinese tribes who massacred entire populations, introduced serfdom, and collected enormous taxes
d. byzantines who gained trust by ruling fairly and using native russians in the government

for the in advanced c;