The correct items:
1. All foreign countries had to pay taxes equally. ย
3. Only the Chinese government could collect tariffs on trade. ย
4. Countries with a sphere of influence should maintain free access to their ports.
The Open Door policy was issued by the United States in 1899-1900 as a series of dispatches from the US Secretary of State to other nations that had trading interests in China -- ย Great Britain, Germany, France, Italy, Japan, and Russia. ย The policy reasserted earlier agreements that all countries should have equal access to ports in China, without undue preference to "spheres of influence" for one nation or another. ย The United States was seeking to maintain an equal footing with other nations in the access to trade in China. ย
