Which of the following embedded options most likely benefits the bondholde（）

A. Interest rate cap on a floating-rate bond.

B. Accelerated sinking fund provision.

C. Put provision at par on a bond that is trading at a premium.

关于闭式胸腔引流的描述正确的是（）。

A.拔管时在患者深呼气屏气时拔除引流管

B.插管部位在腋中线与腋后线之间第6或7肋间隙

C.引流管深入胸腔约3～5cm

D.闭式引流要保证胸腔内气液体克服5～6cm的水柱

E.每日要观察导管是否通畅与引流的质和量