--- Have you heard that Jenny, along with her classmates,        to Harbin for the winter vacation?

--- Really? No wonder I haven’t seen her these days.

A．had gone

B．have been

C．has gone

D．have gone

患者，男性，28岁，右下后牙、右下颌角区反复肿胀3个月；开口困难。检查开口度1指半，右下第三磨牙近中位阻生牙龈充血，挤压有少量脓液溢出，右下颌角咬肌区膨隆明显，质硬，轻度压痛。

此患者如诊断成立，除拔除右下第三磨牙外，还应选择下列哪种措施

A．观察

B．局部理疗

C．大剂量抗生素的使用

D．切开引流

E．病灶刮治术