Answer:
d. A pacifist.
Step-by-step explanation:
A pacifist is a person who abhors of violence and war to solve any dispute. An isolationist is a person who endorse the idea that a country must not intervene in international politics and disputes. Franklin Roosevelt was not a pacifist nor an isolationist. Billy Mitchell was a former US Army general who proposed the need of an independent and modern Air Force in the late 1920s and 1930s. The phrase reflects a moral position from a pacifist.