What was the reason behind the split in the iroquois league during the revolutionary war

Most tribes sought to remain neutral in the conflict, but both British and American agents lobbied the chiefs to fight on their side. The result was the disintegration of the alliance among the six tribes making up the Iroquois League.

Explanation:

The war for American independence had profound effects on the Indians in the southern back-country and in the Old Northwest region west of New York and Pennsylvania. Most tribes sought to remain neutral in the conflict, but both British and American agents lobbied the chiefs to fight on their side. The result of such alliances was chaos on the frontier. Indians on both sides attacked villages, burned crops, and killed civilians. The new American government assured its Indian allies that it would respect their lands and their rights. In December 1777 the Continental Congress promised Oneida leaders that “we shall [always] love and respect you. But in various places local Revolutionaries adopted a very different goal: they sought to use the turmoil of war to displace and destroy all Native Americans.

can someone me with this question:  

1) the end of the conflict between the north and the south didn’t just mark the end of a war; it marked the end of an entire way of life.” which statement best describes what this statement means?  

a) the southerners were no longer free and were controlled by the northern states.

b) the industrial economy in the north was not sustainable.

c) slavery became illegal, which changed completely the south’s labor force and the agricultural economy was destroyed.

d) the states decided to relinquish their independence and return to britain’s rule.