What innovative approach did the Iroquois nations develop to sustain t

What innovative approach did the Iroquois nations develop to sustain themselves in their encounters with other tribes and the Europeans?

A) hostage-taking of members of hostile tribes as well as Europeans
B) a political alliance of the original five Iroquois nations to create a united front
C) clans led by men governing the five nations
D) the building of cliff dwellings in the Northeast for defensive purposes

ANSWER
Answer: B