The MSRB's enforcement role is best described as:

• A. The MSRB enforces all rules for all market participants
• B. The MSRB writes rules and enforces them through its own staff
• C. The MSRB writes rules but relies on other regulators for enforcement
• D. The MSRB enforces only issuer-related rules

Answer: (C)

The main idea is that the MSRB sets the rules but doesn’t enforce them with its own staff. It acts as the rulemaker for municipal securities, creating standards for dealers, banks, and municipal advisers. Enforcement is carried out by other regulators—primarily the SEC and FINRA, along with state securities regulators—who investigate and bring actions for rule violations. This separation means the MSRB guides behavior through rules while external regulators handle compliance and enforcement.

So, the description that best fits is that the MSRB writes rules but relies on other regulators for enforcement.