The most likely reason derivative markets have flourished is that()

A. derivatives are easy to understand and use. 

B. derivatives have relatively low transaction costs. 

C. the pricing of derivatives is relatively straightforward.

桡骨茎突部有一骨纤维性腱管，其间通过的是（）

A.旋前方肌肌腱

B.拇长展肌和拇短伸肌的肌腱

C.桡侧腕长伸肌腱

D.拇长展肌和拇长伸肌的肌腱

E.拇长伸肌和桡侧腕伸肌的肌腱