Which of the following statements about forward and future contracts is FALSE()

A. A future requires the contract purchaser to receive delivery of the good at a specified time. 

B. A predetermined price to be paid for a good is a necessary requirement in the terms of a forward contract. 

C. The primary difference between forwards and futures is that only futures are considered financial derivatives.

键“B18—100”的标注中，“100”的含义是（）。

A.平头普通平键

B.键宽100mm

C.键长100mm

D.圆键