When he was asked about the question where he was last night, he was _____. [ ]

A. at loss

B. in a loss

C. at a loss

D. with losses

下列治疗中首选()

A．距小腿关节(踝关节)内翻位石膏固定

B．距小腿关节外翻位石膏固定

C．人工距小腿关节置换术

D．切开复位内固定，早期功能锻炼

E．观察