All passengers _____ are expected to fasten the seat belts when the plane takes off and lands. [ ]

A. on aboard

B. on board

C. on the board

D. on boards

保险兼业代理机构是指在从事自身业务的同时，根据保险人的委托，向保险人收取（），在保险人授权的范围内代办保险业务的单位。

A、兼业手续费

B、代理兼业费

C、佣金

D、兼业利润分成