The Canfields want to landscape their five-acre yard. They have hired a landscaper to draw the design and to do the actual planning. The landscaper has set up several points where the Canfields can give their inputs, correct anything they do not like and make changes before the plan is finalized. The landscaper has used this method for years as a way to measure his company's customer service performance. The landscaper is using a method of gathering customer information most similar to which of the following methods? ?

A. Process checkpoint evaluations
B. Requirements research
C. Critical incidents studies
D. Trailer calls
E. Market-oriented ethnography