Evergreen Air Center is the world's biggest parking lot for unwanted aircraft. Airlines pay a monthly fee from $750 to $5,000 to mothball their unneeded airplanes there. Its location is on 1,600 acres of Arizona desert near Tucson. The Southwest climate of dry, warm air serves as a cheap and effective airplane preservative against rust. Evergreen's location is: a competency. a sustainable advantage. a competitive identity. a core benefit proposition. an innovative distinction.

a Competency

Explanation:

Competency refer to set of capabilities an enterprise possesses relating to performance of a task in an efficient manner in a given specific situation.

Competencies are the sum total of skills, knowledge and capabilities.  These are developed over time with application of skills and knowledge.

In the given case, Evergreen reaps benefits with respect to parking area for unwanted aircraft owing to space it possesses and the climate of the location which protects the aircraft from dust and rusting.

This represents a case of competency which has built up over time owing to a capability which has emerged out of application of skills, knowledge and environmental advantage.