b) John J. Pershing

John J. Pershing was appointed to command the American Expeditionary Forces (AEF) in World War I. Pershing, who had previously served in the Spanish-American War and the Philippines, was selected by President Woodrow Wilson for his strong leadership skills and military experience. Under his command, the AEF grew from a few thousand men to over two million. Pershing was known for insisting that American soldiers fight as independent units under American command, rather than being integrated into Allied units. This stance helped to establish the United States as a world military power.