男性，50岁。因结肠癌于3个月前手术治疗时输血800ml，术前肝功能正常，HBsAg（-），近1个月来略感消化不良，检查ALT380U／L，AST290U／L，TBIL46μmol／L。

下列检查有助于诊断的是（）

A.抗HAV-IgM

B.乙型肝炎病毒指标两对半

C.HCV-RNA和抗HCV

D.HDAg抗HD-IgM

E.抗HEV

Frame Relay is simplified form of (51) , similar in principle to (52) , in which synchronous, frames of data are routed to different destinations depending on header information.

Packets are routed throught one or more Virtual Circuits known as (53) . Most Virtual Circuits are (54) , which means that the network provider sets up all DLCI connections at subscription time. (55) are also part of the Frame Relay specification. They privide a link that only lasts only as long as the session.

（53）是（）

A.DLCIs

B.HDLCs

C.SDLCs

D.DLs