女性，56岁，间断突发右侧面部闪电样锐痛1个月，疼痛多位于右侧上唇、鼻翼、口角、颊黏膜处，常于进食、洗脸、刷牙时发作，每次持续1～2分钟，发作间期无症状，每日发作1～2次。

本病最常见的责任血管是（）

A.小脑上动脉

B.小脑前下动脉

C.小脑后下动脉

D.椎动脉

E.静脉

If money is invested at r percent interest, compounded annually, the amount of the investment will double in approximately years．If Pat’s parents invested $5,000 in a long-term and that pays 8 percent interest, compounded annually, what will be the approximate total amount of the investment 18 years later, when Pat is ready for college ？（）

A.$20，000

B.$15，000

C.$12，000

D.$10，000

E.$9，000