What is the service volume of a DME station?

The service volume of a Distance Measuring Equipment (DME) station is typically defined as the range and capacity these systems can support. A DME station provides distance information from the station to the aircraft, and it is designed to operate within specific parameters for effectiveness and reliability.

The correct answer identifies a service volume of 199 nautical miles, which is consistent with the established standards for DME operations, particularly in terms of coverage for en-route aircraft. This range allows for optimal performance across a significant operational area, enabling pilots to receive accurate distance measurements while flying at high altitudes.

Moreover, the capability to support up to 100 aircraft simultaneously reflects the expectation of air traffic, particularly in busy airspace, and is aligned with the rules governing DME stations to ensure that they can handle multiple users without degrading the quality of the data provided.

In contrast, the other options specify different ranges and capacities that do not match the established standards for DME service volumes. Thus, option C stands out as the correct representation of a DME station's operational capabilities, ensuring that pilots can depend on accurate distance readings within a well-defined range.