Which ATC facility should you expect a clearance for takeoff from while holding short of an active runway?

When holding short of an active runway, a pilot should expect to receive a takeoff clearance from the Tower. The Tower is responsible for controlling all aircraft movement on the runways and taxiways at an airport. This includes issuing clearances for takeoff and landing.

The Tower's primary function is to ensure safe and orderly traffic flow within the airspace surrounding the airport. It communicates directly with pilots who are on the runway or preparing for takeoff and landing, ensuring that any necessary instructions are given clearly and that all safety considerations are taken into account.

While Ground Control manages movement on the taxiways and some aspects of airport operations, it does not issue takeoff clearances. Approach Control manages the flow of aircraft in the vicinity of the airport, particularly during arrivals and departures, but is not involved with the day-to-day operations on the active runways. A Flight Service Station provides information services like weather but does not have any authority over runway operations or clearances. Thus, the Tower is the correct facility for obtaining a takeoff clearance while holding short of an active runway.