Which statement best summarizes the qing dynasty’s trade policy before the early 1800’s

Before the early 1800s, the Qing dynasty didn't allowed foreign nations to trade with them or to establish trading posts in its territory.

Explanation:

The Qing Dynasty (1644-1911) was the last imperial dynasty to rule over China, followed by the last of Chinese origin, the Ming. They were of Manchu origin.

In the 18th century, the Qing empire experienced a new era of glory as it succeeded in taking advantage of European colonies for economic gain. However, this led to the Opium Wars (1839-1842 and 1856-1860) against Britain, both lost by the Chinese. Thus, China was forced into trade agreements that benefited the British more than them. In the 19th century also followed the Franco-Chinese War (1883-1885) and the First Sino-Japanese War (1894-1895). The Chinese lost both of them.  

Towards the end of the Qing Dynasty, the real power of the country laid in the hands of foreigners. In addition, internal disputes prevailed as a result of poor living conditions and national currents that would exert foreign powers. This led to several major revolts such as the Taiping rebellion (1850-1864), the Nian rebellion (1853-1868) and the Boxer rebellion (1898-1901).

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.