The successful spread of a virus depends on how long it can (74) unnoticed, before its presence is made known by the activation of side-effects. For example, many viruses (75) their code to avoid recognition.

A．move

B．replicate

C．backup

D．die out

关于Eudemon200防火墙安全特性描述正确的是（）。

A、Eudemon200防火墙支持ACL功能

B、Eudemon200防火墙支持报文统计（如IP连接数量监控）功能

C、Eudemon200防火墙支持和其它各厂商的IDS联动

D、Eudemon200防火墙有专门的攻击防范特性