I feel like the answer is probably false as it uses the words strict;y, meaning only.
A., because safeguard and protection align to be similar, therefore the environmental recourses are protected by the laws, effecting the economy greatly
The correct items:
1. All foreign countries had to pay taxes equally.
3. Only the Chinese government could collect tariffs on trade.
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 -- Great Britain, Germany, France, Italy, Japan, and Russia. 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. The United States was seeking to maintain an equal footing with other nations in the access to trade in China.