As nobody here knows what’s wrong with the machine, we must send for an engineer to _______ the problem.

A．raise

B．face

C．present

D．handle

某患者，大面积银汞充填，要求修复治疗。检查：MOD大面积银汞充填体，牙冠剩余硬组织少，仅残留颊舌薄壁，无松动、无叩痛，已行完善根管治疗。最佳的治疗方案是（）

A.嵌体

B.高嵌体

C.桩核加全冠

D.烤瓷全冠

E.铸造金属全冠