What is the role of the iROC in overseeing trading firms?

The role of the iROC (Investment Industry Regulatory Organization of Canada) is primarily focused on regulating and supervising investment dealers. This involves ensuring that these firms adhere to the necessary rules and standards that govern the industry, which helps in the protection of investors. By monitoring trading practices and imposing regulations, the iROC works to maintain fairness and order in the markets, which is critical for instilling confidence among investors and ensuring smooth market operations.

The other options represent functions that are outside the scope of what the iROC does. Issuing new stocks is typically the responsibility of public companies and underwriters in the initial public offering process. Managing the national currency supply falls to a country's central bank, while conducting financial audits on public companies is generally performed by independent accounting firms rather than a regulatory body like the iROC. Thus, the correct answer accurately reflects the iROC's mission and functions in the financial industry.