The correct answer is C. The Monroe Doctrine
The Monroe Doctrine was elaborated by John Quincy Adams and attributed to President James Monroe in 1823, and it was synthesized in the idea that the Americas should remain free from European bonds. It posited that any intervention of Europeans in the territory of the Americas was seen as an act of aggression that required the intervention of the United States. It was conceived by its authors as a proclamation of the United States against European colonialism, but at the same time, it marked the beginning of the American expansionism. Anyway, there were several European interventions during the 19th-century in Latin America that counted with the support or omission of the United States, like the British occupation of the Falklands, the British-French blockade of the River Plate, and the Spanish invasion of Dominican Republic, among others.