How Did U.S. Geography Encourage Isolationism

How did U.S. geography encourage isolationism?

A) The United States was so close to Canada and Mexico that expansion there seemed natural.
B) The United States was a relatively small country compared to Canada or Mexico, making it less willing to engage in armed conflicts over land.
C) The United States was protected on both sides by vast oceans that discouraged attack from Europe or Asia.
D) The United States had just concluded the Civil War and was more concerned with domestic affairs than foreign ones.
E) The United States was beginning to prosper and look for new markets for its products and workers for its factories.