PLZ HELP What were the causes of the Treaty of Kanagawa? What were the effects of this treaty?

The Treaty was the result of an encounter between an elaborately planned mission to open Japan and an unwavering policy by Japan's government of forbidding commerce with foreign nations. ... He did not, however, open Japan to trade. EFFECT: Treaty of Kanagawa signed with Japan. In Tokyo, Commodore Matthew Calbraith Perry, representing the U.S. government, signs the Treaty of Kanagawa with the Japanese government, opening the ports of Shimoda and Hakodate to American trade and permitting the establishment of a U.S. consulate in Japan.

Ithink the answer is b