This question is incomplete, here´s the complete question.
Why was it strange when John Hay announced that all nations had agreed to an Open Door Policy in China?
A. because it was the Boxers’ idea
B. because American businesses had no interest in China
C. because it angered the anti imperialist forces back home
D. because none of the other foreign powers had accepted it
Answer: D. because none of the other foreign powers had accepted it
Explanation:
In 1900, when John Hay announced that all nations had agreed to the Open Door policy, he had actually interpreted the evasive responses from Great Britain, Germany, France, Italy, Japan, and Russia as a positive consent in principle.
Furthermore, even after that, and despite several treaties referring to the Open Door Policy, competition over getting special concessions in China still remained.