Answer:
A. They restricted European trade to the city of Canton.
Step-by-step explanation:
Haijin was a series of related Chinese isolationist policies that restricted private maritime trade and coastal settlement, during most of the Ming Dynasty and some of the Qing. Imposed, in principle, to fight against the Japanese piracy called wakÅ the prohibition was finally ineffective, the contraroi imposed great difficulties in the coastal cities as well as the honest merchants of the sea. Piracy descended to insignificant levels after the general abolition of politics in 1567. Subsequently the Qing Dynasty adopted a modified form. This produced the Canton system of the Thirteen Factories, but also the opium contraband that led to the opium wars with Great Britain and other European powers in the 19th century. The policy was also imitated by both Tokugawa Japan (as Sakoku) and by Joseon of Korea, which became known as the "Hermit Kingdom", before they opened militarily in 1853 and 1876.