Final answer:
If a criminal or civil complaint involving a real estate transaction has been filed against a licensee, they must notify the Commission orally or in writing.
Step-by-step explanation:
If a criminal or civil complaint involving a real estate transaction has been filed against a licensee, he/she must notify the Commission orally or in writing. This means that the licensee can inform the Commission by speaking to them directly or by submitting a written notification. The notification can be delivered in person or by certified mail, but it is not specifically required to be sent by certified mail.