保险费是按赔偿限额选择适用的费率计算，无累计赔偿限额的保险费计算公式为（）。

A.保险费=累计赔偿限额×适用费率

B.保险费=每次事故赔偿限额×适用费率

C.保险费=场地占有面积×单位面积保险费

D.保险费=赔偿限额×事故发生次数×单位保险费

Mr. Smith is handsome and kind and he is one of _______ in our school .

A．a popular teacher

B．more popular teacher

C．most popular teachers

D．the most popular teachers