电子商务的系统安全就是对交易中涉及的各种数据的______进行保护。

A．有序性、完整性、可靠性
B．可靠性、完整性、可用性
C．可重复性、可控性、有序性
D．可重复性、完整性、可靠性

（）means a technique using digital codes which enables a radio station to establish contact with, and transfer information to another station or group of stations and complying with the relevant recommendations of the CCIR.

A.DSC

B.MSI

C.EGC

D.NBDP