John Borrows (2017) tells us that the Haudenosaunee Confederacy was initially made up of five Iroquoian nations: Mohawk, Oneida, Onondaga, Cayuga, and Seneca. Which nation became a part of the Confederacy later, leading to its constitution as Six Nations?

O Choctaw
O Tuscarora
O Huron
O Tlingit