Bond is selling at a discount relative to its par value. Which of the following relationships holds（）

A. yield to maturity ＜ coupon rate ＜ current yield.

B. current yield ＜ coupon rate ＜ yield to maturity.

C. coupon rate ＜ current yield ＜ yield to maturity.

下列活髓切断步骤中正确的是（）

A.去腐、冲洗、然后隔湿、消毒

B.用普通涡轮钻针快速去除冠髓

C.肾上腺素棉球加压止血

D.1：5FC浴后氢氧化钙盖髓

E.氧化锌丁香油黏固粉和羧酸锌水门汀垫底后充填