--- Believe it or not, I ______ an old friend of mine while abroad.

--- Oh, it’s a small world.

A．came up

B．came out

C．came across

D．came about

患者，女，50岁，家庭主妇。二个月前逐渐出现右手臂部疼痛，扭毛巾和倒开水时疼痛症状加重。体查：颈部无异常，臂丛牵拉试验阴性，右手腕桡骨茎突处压痛明显

如果采用封闭疗法，普鲁卡因的极量是多少（）。

A.200mg

B.400mg

C.600mg

D.800mg

E.1000mg