【单选题】

SECRET SHOPPERS

Tim Wright knows all about making companies more efficient. His firm,Check-up, sends ’secret shoppers’ into retail and leisure companies (29) order to make sure that customers are receiving good service.After (30) visit, the secret shoppers prepare a report for the company to let them know (31) good or bad the service was.
’Companies like to know,’ says Mr Wright,’ that (32) customers go into a store just a few minutes before closing time, they will (33) get good service.’Check-up (34) set up in the west ofEngland in 1992 and (35) two years moved to London so it could offer a nationwide service. (36) the last three years,Check-up’s profits have (37) dramatically as companies have come to realise (38) great importance of good customer service. Having started with just three employees,Check-up now has a staff (39) sixty-five and last week (40) an important new contract with a major supermarket chain.
A．in
B．by
C．on