单项选择题
A．paying less B．selling many products at once C．bargaining with each buyer D．selling goods at a higher price
A．the student finally gave up B．the student made rapid progress by practicing more carefully C．the calligrapher was strict with his students D．old newspaper is not useful
A．the practice of turning goods into money B．making goods available for purchase C．the customer-centered approach D．a form of persuasive salesmanship