Mississippian Chiefdoms Based in Centers with Large Platform Mounds Arose

Mississippian chiefdoms based in centers with large platform mounds arose __________________.

A) after buffalo became the primary source of dietary protein in the region
B) as a response to the arrival of Spanish conquistadors in the area
C) after Mesoamerican maize was added to the regional diet
D) after the previous occupants of the area were displaced by an invasion