What is the primary role of the SEC (Securities and Exchange Commission)?

The primary role of the Securities and Exchange Commission (SEC) encompasses multiple responsibilities essential for the functioning of the financial markets, and this is why the correct answer includes all of the options provided.

The SEC's fundamental mission is to protect investors. This is achieved through the enforcement of securities laws that ensure transparency and fairness in the securities markets. By safeguarding investors from fraudulent practices and ensuring they have access to important information, the SEC helps maintain public confidence in the financial system.

Additionally, the SEC plays a crucial role in governing US stock exchanges. It regulates the exchanges and oversees their activities to maintain orderly and efficient markets. This governance is important to uphold a level playing field where no party has an unfair advantage, fostering fair trade practices.

Lastly, while the SEC itself does not directly establish accounting standards, it does endorse accounting standards such as those set by the Financial Accounting Standards Board (FASB). The SEC plays an oversight role by reviewing these standards to ensure they are in the best interest of investors and reflect the economic realities of the transactions reported by public companies.

Therefore, the SEC's comprehensive mandate includes protecting investors, governing stock exchanges, and influencing accounting standards, which collectively underscores the option that states all of the above as its primary role.