消除由于房室结折返引起的阵发性室上性心动过速的首选药是

A．奎尼丁

B．利多卡因

C．普鲁卡因胺

D．苯妥英钠

E．维拉帕米

At sea，all required GMDSS equipment（other than survival craft equipment）must be proven operational by（）.

A.daily testing

B.either A or C

C.operational use of the equipment

D.testing at least every 48 hours