Which of the following is a separate departure route from an airport or terminal area to an enroute point?

The correct choice, which is Preferential Departure Route (PDR), is designed to provide a specific path that aircraft will follow after departing from an airport or terminal area to an enroute point. These routes are established to enhance traffic flow and efficiency for departures, offering a standardized way for aircraft to climb away from the airport while minimizing conflicts with other air traffic. By utilizing these preferential routes, air traffic controllers can effectively manage departures, ensuring that aircraft are quickly and safely directed towards their intended flight paths.

In contrast, other route types may not specifically define a separate departure route in the same focused manner or could have different purposes. For instance, Standard Departure Routes and Controlled Departure Routes have broader applications and may involve more complex procedures or flexibility, which are less ideal for simply establishing clear departure paths. An Assigned Departure Route serves as a directive for a specific flight but lacks the specificity and standardization associated with a Preferential Departure Route. Thus, the PDR stands out as the most fitting option for the definition given in the question.