It's A). to protect workers' rights and improve working conditions
Answer: The United States had taken possession of the Philippines (as well as Guam and Puerto Rico) in 1898, after winning the Spanish-American War. Thus US interest in Asia was heightened.
At the same time, other nations had begun competing for "spheres of influence" in trade access with China.
Further detail:
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.
C. The rules of inheritance on tribal lands
This is because there is no really particular rule of inheritance because it doesnt concern the government
U.S. Supreme Court ruled on March 3, 1919, that the freedom of speech protection afforded in the U.S. Constitution's First Amendment could be restricted if the words spoken or printed represented to society a "clear and present danger."