What must a registered person do to participate in private securities transactions?

To participate in private securities transactions, a registered person is required to provide written notification to her employer. This requirement ensures that the employer is aware of the registered person's involvement in these transactions, which might present potential conflicts of interest or compliance issues. Notifying the employer also allows the firm to assess risks associated with the transaction and ensures that the employee remains compliant with relevant regulations and internal policies. Supervisors or firm management may also need to make decisions regarding the suitability and compliance of these transactions to protect both the firm and its clients.

In contrast, seeking client approval, obtaining verbal approval from a supervisor, or submitting the transaction for ratification by the SEC are not standard requirements for participating in private securities activities. These other actions do not fulfill the necessary obligation to inform the employer in a formal manner, which is why the correct answer emphasizes the importance of written notification to the employer.