Answer:
b. Japanese pirates undermined the Ming dynasty's economic isolationist policies.
Explanation:
At the beginning of the Ming Dynasty, after the devastation of the war that expelled the Mongols, the emperor of Hongwu imposed severe restrictions on trade (the haijin or the "prohibition of the sea"). Believing that agriculture was the basis of the economy, Hongwu favored industry in general, including the mercantile industry. Partially imposed to deal with Japanese piracy amid the cleansing of Yuan's supporters, the ban on the sea was completely counterproductive; in the sixteenth century, piracy and smuggling were endemic and consisted mainly of Chinese who had been stripped by politics. China's foreign trade was limited to expensive and irregular tribute missions, and resistance to them among the Chinese bureaucracy led to the abandonment of Zheng He's fleets. Piracy fell to insignificant levels only after the end of politics in 1567.