What Most Accurately Describes Imperialism Between 1870 and 1917

What most accurately describes imperialism between 1870 and 1917?

A) The US was the leading imperialist nation in the late 19ᵗʰ century.
B) The US was primarily concerned about expanding freedom in relatively poor nations in Africa.
C) The "Roosevelt Corollary" and the Monroe Doctrine were the primary documents that outline the US foreign policy.
D) European nations like England and France oriented their annexation efforts toward Latin America.