The idea of the United Nations was created to insure world security and was devised when Britain's Churchill and this man signed the Atlantic Charter.

a. Stalin

c. de Gaulle

b. Roosevelt

d. Truman

The idea of the United Nations was created to insure world security and was devised when Britain’s Churchill and President "Roosevelt" of the United States signed the Atlantic Charter, since it was during this meeting that the two leaders mapped out ideas for the post-war world.