Which type of communications system employs predefined frequency settings for quick access?

The correct choice is the Preset Communication System. This type of system is specifically designed to utilize predefined frequency settings, allowing users to quickly access designated channels without manual tuning. This feature is essential in tactical communications, where speed and efficiency can significantly impact mission success. By having these frequencies preset, operators can focus on executing their tasks rather than wasting time dialing in frequencies, especially in high-pressure or rapidly changing environments where every second counts.

Other communication systems, such as Analog Radio and Digital Radio, may require manual selection or adjustment of frequencies, which can slow down response time. Manual Frequency Radio relies heavily on the user to tune to the desired frequency, making it less efficient in situations where rapid communication is crucial.