Which of the following is necessary for the proper functioning of alarm systems?

Regular system testing is essential for the proper functioning of alarm systems because it ensures that all components are working correctly and effectively. Testing helps identify any faulty equipment, ensures that alarms and sensors are responsive, and checks the communication lines with monitoring services. By routinely assessing the system's performance, you can ensure that the security measures in place will operate as intended in the event of an emergency or breach.

This proactive approach to system maintenance helps to prevent potential failures during critical moments, providing peace of mind that the security measures taken will be reliable. While other options, like employee training or budget reviews, can contribute to a holistic security strategy, they do not directly address the operational integrity of the alarm system itself as regular testing does.