What was the most significant reason for abandoning the rust belt for the sun belt?

A. It acted as a system of checks and balances.

Explanation:

Magna Carta or call it by another name the Great Charter was the charter of liberties that was granted by England's King John to the barons ( wealthy merchants) in a threat of a civil war. Foreign policies and taxation put a burden of the Englishmen and the document of Magna Carta of 1215 assured that the power of ruler is within a system of check and balance. Later this document was evolved and seemed as an expression of freedom from the oppression of the Crown.