How did Marius change Rome's government?

Marius created a standing army, permitted the poor's enlistment, and provided retirement benefits for veterans. He also reformed the organization of the army. These all allowed Marius to defeat the barbarian invasion. The army that he created drove the expansion of the Roman Empire for years to come

Explanation:

cultural/diplomatic relations. most medieval japanese   culture has chinese origins. writing, architecture etc.

letter a is the answer