The answer is option A: He focuses on the unity and strength of the American people and peoples of other nations who believe in freedom.
In Franklin D. Roosevelt's famous speech, he addressed the Congress to formally declare war on Japan and he appealed to the unity and strength of the American people to support the war and overcome the current difficulties. This is clear in the following excerpts taken from his speech: "...the American people, in their righteous might, will win through to absolute victory.", and "With confidence in our armed forces, with the unbounding determination of our people, we will gain the inevitable triumph, so help us God."