Final answer:
Standard Instrument Departure (SID) provides transition from the runways to the appropriate en route structure, facilitating a safe and efficient movement from the airport to en route airspace.
Step-by-step explanation:
In reference to Standard Instrument Departure (SID), the option that provides transition from the runways to the appropriate en route structure is (a). SIDs are used by aircraft to transition safely from the airport to the en route airspace. These procedures are designed to expedite traffic flow and to minimize air traffic control communications, whilst also avoiding obstacles and potentially hazardous areas. The correct transition according to this standard is 'from the runways to the appropriate en route structure'. SIDs often include noise abatement procedures to minimize noise pollution in areas surrounding the airport.