Answer:
C) Was part of an attempt by the United States to acquire Cuba.
Explanation:
The Ostend Manifesto was a written document that invited the American Government to purchase Cuba from Spain, and in case Spain refused to sell, to invade Cuba with military force.
It takes the name from the city of Ostend, Belgium, were three American diplomats: James Buchanan, Pierre Soulé, and John Y. Mason met to draft the document.
The rationale behind the manifesto was to enlarge the U.S. territory, to protect national security from a weak, but anyways hostile Spain, and to establish a new slave state.
This manifesto was largely rejected by northerners, who saw it as just another attempt to extend slavery, and it in the end, it failed to gather support.