抽样误差指的是（）

A.测量个体数据之间的差别

B.测量个体数据和样本指标的差别

C.测量个体数据和总体指标的差别

D.研究总体指标之间的差别

E.抽取的样本指标与总体指标的差别

Yesterday I was about to leave for the market _____ my boss called and asked me to go back to the office at once．

A．when

B．while

C．as

D．because