Answer:
Joint Chief of Staff is the correct answer.
Step-by-step explanation:
President Franklin D Roosevelt and Prime minister of UK Winston Churchill had decided to establish the joint chief of staff during Arcadia conference. The first chief of staff was George C. Marshall. He was named joint chief of staff at the onset of second world war. Marshall increased the size of the US army and devised the operation overlord in 1944. He also started the economic recovery program for the Europe which came to be known as Marshall Plan.