Answer:
C. a retail communication
Explanation:
FINRA is a non governement corporation that enable investor or firm to participate in the market by safeguarding their rights. It has been divided into two category:
Correspondence: It is a communication to 25 or less existing client or prospective clients. Under correspondence, Institutional communication and public appearances are not subject to pre principal approval.
Retail communication: It is communication to more than 25 existing client or prospective client, excluding institutional communication and public appearance.
In the given case, It is a communication to 30 retail clients, therefore is a retail communication