When should you advise aircraft to expect requested altitude?

The correct choice indicates that advising aircraft to expect their requested altitude approximately 10 minutes after departure is appropriate. This timeframe allows air traffic controllers to manage air traffic effectively, as it provides necessary spacing between departing flights. Typically, during the initial stages of flight after takeoff, aircraft are still climbing to their assigned altitude, and various factors such as airspace restrictions and traffic may prevent immediate acknowledgment of altitude requests.

This approach helps maintain safety and efficiency in controlled airspace. It aligns with standard procedures for communication and ensures pilots are informed about their expected altitude as they progress on their flight path, but without overwhelming them with information too early in their ascent. Thus, providing an expectation after 10 minutes is a pragmatic choice, as it gives the controller adequate time to assess and relay updates based on the current traffic situation.