The answer is that it opened treaties with the Americans or letter c. It is also called Perry Convention and it is the first treaty that Japan had with Westerners. This happened when Commodore Mathew Perry sailed into Tokyo Bay and made demands for supplies for his war fleet by opening their ports. He gave them time to think over. After realizing they were no match for his warships, they signed a treaty with the United States which marked the end of their seclusion.