Final answer:
Positive Control Service (PCS) is an air traffic control service for aircraft en route between destination and departure terminal areas, maintaining safe separations using radar and proper coordination.
Step-by-step explanation:
The service mentioned in the question that provides separation and control of aircraft (a/c) operating between departure and destination terminal areas is known as c. Positive Control Service (PCS). This service is an air traffic control service that is primarily provided in the en route environment, which includes the airspace over regional areas between airports.
The role of PCS is to ensure a safe and efficient flow of traffic between different terminal areas by providing services such as route planning, separation of aircraft, and coordination with other air traffic control sectors when necessary. It operates through radar monitoring, communication systems, and established air traffic control procedures. The PCS is crucial in maintaining safe distances between aircraft, which is especially important in mixed aircraft scenarios like the one described in Figure 2.34 where different types of planes such as Boeing 747 and Douglas DC-3 are operating concurrently at different altitudes and directions.