Which of the following must a registered representative disclose as an outside business activity (OBA)...

FINRA Rule 3270 requires registered representatives to disclose all outside business activities that involve compensation or could reasonably be perceived as a conflict of interest.

C is correct because serving as a board member for a publicly traded company is a business activity requiring disclosure, even if compensation is indirect.

A is incorrect because volunteer work for charities does not require disclosure.

B is incorrect because acting as a trustee for a personal or family estate is generally not considered an OBA.

D is incorrect because unpaid board membership for a not-for-profit entity does not typically require disclosure.