The primary reason the United States advocated the Open Door Policy was to

Responses
A protect and broaden U.S. trade with China.protect and broaden U.S. trade with China.
B expand the concept of the Monroe Doctrine to Asia.expand the concept of the Monroe Doctrine to Asia.
C justify our taking the Philippines as a US colony.justify our taking the Philippines as a US colony.
D justify the extension of American colonies into the Far East.justify the extension of American colonies into the Far East.