Which of the following is NOT one of the conditions that must be met for a trade to be considered an arbitrage()

A. There is no risk. 

B. There are no commissions. 

C. There is no initial investment and there is a guaranteed profit.

美国小举校长是学校的行政首长，向学监负责、执行学区理事会（）的有关决议及管理学校日常行政事务。