The customers at Marielle's coffee shop want to grab a quick cup of coffee before boarding the commuter train into the city. The sign in the window promises "Quick, In-and-Out Service," and usually Marielle's keeps that promise. But one morning, customers were frustrated when the staff behind the counter showed more interest in gossiping about their social lives than in waiting on customers. Marielle's shop is suffering from a ________ gap.
A. knowledge
B. standards
C. social expectations
D. delivery
E. communications
Answer: D. delivery