the man will have to wait all day_____the doctor works faster.Aunless B if C whether D that

the man will have to wait all day_____the doctor works faster.
Aunless B if C whether D that

A 除非的意思
除非这个医生动作快点 不然我们得等他一天

选A,除非医生工作快点，要不然这人要等上一整天。