—Excuse me, may I take a seat here?

—________ The man on the seat has already left. [ ]

A. You'd better not.

B. Yes, please.

C. No, you can't

初产妇，26岁，孕38周，临产12小时， * * 流水2小时，胎心率140次/分，宫口开8cm，S+2，入院后2小时复查，宫缩50秒，间歇3分钟，宫口扩张及先露下降无进展， * * 检查：小囟门在7点处，矢状缝在右斜径上，正确的诊断是

A．胎儿窘迫

B．胎膜早破

C．中骨盆狭窄

D．协调性宫缩乏力

E．持续性右枕后位