Letter D is correct.
Since Haiti had freed itself from slavery, the United States did not support the revolution. The American government feared a successful slave rebellion would take place in the South. At that time, wealthy plantation owners (such as those in South Carolina) were pressuring the U.S government afraid of losing their source of power and prestige which was entirely dependant on slavery. In fact, in order to isolate Haiti and prevent slave revolution from spreading, President Thomas Jefferson joined with European nations to place an embargo on Haiti.