The difference between the travel agent’s role and that of most other retailers is that （）. A: thetravelagentsneverpurchaseaproductforresaletotheircustomers B: thetravelagentmakesthepurchaseonlywhenacustomershasdecidedonone C: thetravelagentdoesnotneedtopurchaseaproductforresale D: thetravelagentmakesthepurchasebeforethecustomerasksforit