What are the methods of communication involved in ACJIS transactions?

The correct choice emphasizes that ACJIS transactions rely on secure electronic communications and database queries. This is fundamental because the ACJIS system is designed to handle sensitive criminal justice data, requiring methods that protect the integrity and confidentiality of the information being exchanged. Secure electronic communications ensure that data is transmitted safely over networks, minimizing the risk of interception or unauthorized access. Database queries are essential to accessing, retrieving, and processing information within the ACJIS, facilitating efficient law enforcement operations and data management.

Other options like regular postal mail, public announcements, and phone calls do not align with the technological and security needs involved in managing and sharing criminal justice data. Such methods may be appropriate for less sensitive information but are not suitable for the high-security requirements that ACJIS transactions demand.