The Financial Industry Regulatory Authority (FINRA) is a self-regulatory organization responsible for overseeing brokerage firms and registered securities representatives in the United States. Its primary mission is to protect investors and ensure market integrity by enforcing rules governing ethical conduct, disclosure, trading practices, and licensing. FINRA operates under the oversight of the Securities and Exchange Commission (SEC), creating a regulatory structure that combines federal authority with industry expertise. Unlike the FDIC, FINRA does not insure deposits, and unlike the Federal Reserve, it does not manage monetary policy or issue currency. Financial management texts emphasize FINRA's role in supervising broker-dealers, administering qualification exams, and resolving disputes through arbitration and mediation. Option A correctly identifies FINRA's core responsibility.