Answer: The Confederate attack on Fort Sumter
Lincoln believed that American democracy meant equal rights and equality of opportunity. But he drew a line between basic natural rights such as freedom from slavery and political and civil rights like voting. He believed it was up to the states to decide who should exercise these rights.
The correct answer to this open question is the following.
You forgot to include the options for this question. However, we can say the following.
This excerpt from John Hay's Circular Letter became part of the "Open Door policy."
Yes, it is true that Jhon Hay, Secretary of State in the United States government created the idea of the open door policy for China at the beginning of the 1900s. What was the goal of the US government? To secure a favorable position to trade with China, offering the government of China the kind of respect for their history, traditions, and territory. So it was the first official agreement the United States wrote to became the international trade policy with Asian countries.