Answer:
To ensure that U.S. businesses could operate in China.
Step-by-step explanation:
The open door policy was established in 1899 and 1900 by the United States of America, so as to protect and accord equal privileges to all the countries trading with China.
The main reason the United States announced the Open Door Policy is to ensure that U.S. businesses could operate in China.
Prior to joining the World Trade Organization (WTO), China wasn't open about it's economic activities or policy to other countries across the world. This simply means the Chinese government was very secretive about the happening in it's country and as such would not allow outsiders to see what it was doing or it's engagements.
However, joining the World Trade Organization (WTO) made them to be more open to other countries, which was a key factor for their unprecedented economic growth and development.
Hence, China was able to trade globally, capturing many markets and attracting foreign investment which boosted it's economy greatly.