The correct answer is C) the Selective Service Act.
The 1940 legislation that showed Roosevelt's commitment to war preparedness was the Selective Service Act.
The Selective Service Act of 1940 was passed by the United States Congress on September 16, 1940. It was important legislation because service was obligated for men although it was peacetime. Let's remember that the United States had decided to maintain a neutrality foreign policy regarding the conflict in Europe. So we could say that this was peacetime. However, the decision to ask all men between 18 and 64 years all to register to the conscription service, showed that the Roosevelt administration foresaw that the "winds of war" were coming. The United States entered World War II after the Pearl Harbor attack of December 1941.
