The Existence of High Exit Barriers Such as Ownership of Specialized

The existence of high exit barriers such as ownership of specialized assets (e.g., large aircraft) in the airline industry indicates that

A) customers are relatively weak because of the high switching costs created by frequent flyer programs.
B) the industry is moving toward differentiation of services.
C) the competitive rivalry in the industry is severe.
D) the economic segment of the external environment has shifted, but airline strategies have not changed.