The correct answer is D) by an order of President Truman.
The loyalty boards were created by an order of President Truman.
The political situation in the United States was of fear during the Red Scare. The United States Congress was investigating the presence of Communists in the government. American citizens lived in doubt and fear. That is when President Harry S. Truman ordered the creation of loyalty boards in the federal government. On March 21, 1947, he issued an order to start with loyalty revisions on federal government employees. Truman expected that every single US federal employee showed loyalty to the United States.