Answer:
Answer is C, were directed to the imperial powers in Europe and Asia.
Explanation:
The "Open door notes" which was initially known as the "Open door policy" , was created or proposed in 1899 by John Hay who was the the secretary of state.
The aim or purpose of the policy or note was that the Chinese market should be open to all parties, that is , countries. This means that , no particular country should gain or have total control over that region.
It should be noted that during that time, there was intense competition to exert control over China among the countries in America and Europe. This is because, at that time the Chinese government was not that strong.
Then , the open door policy or note was created to avoid or prevent conflict that may arise or occur over the Chinese market.