What entity is likely to be the subject of a complaint regarding a process server's conduct?

The correct choice is a certificate holder because this individual is the one directly engaged in the responsibilities of serving legal documents. If there is an issue with the process server's conduct—such as not following legal protocols, mishandling documents, or behaving unprofessionally—it is typically the certificate holder who would face complaints from affected parties.

A certificate holder is accountable for their actions in the field, and clients or parties receiving service might raise concerns if they believe the process server has acted inappropriately or unlawfully. This oversight ensures that process servers uphold the integrity of the service they provide and maintain trust in the legal system.

The other entities listed, such as certification agencies, training institutions, and community colleges, generally play supportive roles in the development and oversight of process servers but are not directly involved in active service or client interactions. They may provide training or certification but are not the focus of complaints regarding individual conduct.