What is the name of the investigative arm of Congress, established in 1921, that audits and evaluates federal programmes for efficiency and effectiveness?

• A Congressional Budget Office
• B Office of Management and Budget
• C Government Accountability Office ✓
• D Inspector General's Office

The GAO, originally the General Accounting Office, is headed by the Comptroller General, who serves a 15-year term and cannot be removed by the president.