When we credit the successful people with intelligence, physical strength or good luck we are making excuses for ourselves because we fall ______ in all three.

A．rare

B．lacking

C．short

D．scarce

影响服务期望的因素有很多，下列因素属于不可控因素的是()。

A、产品的定价

B、企业的服务承诺

C、产品的口碑

D、顾客的要求