六脉动的换流器，其直流侧和交流侧的特征谐波是什么（）。

A.交流侧的特征谐波是6n次谐波

B.直流侧特征谐波是6n-1次谐波

C.交流侧的特征谐波是6n+1次谐波

D.直流侧特征谐波是6n次谐波

NAC’s(Network Access Control) role is to restrict network access to only compliant endpoints and (31) users. However, NAC is not a complete LAN (32) solution; additional proactive and (33) security measures must be implementeD. Nevis is the first and only comprehensive LAN security solution that combines deep security processing of every packet at 10Gbps, ensuring a high level of security plus application availability and performance. Nevis integrates NAC as the first line of LAN security (34) . In addition to NAC, enterprises need to implement role-based network access control as well as critical proactive security measures--real-time, multilevel (35) inspection and microsecond threat containment.

A．port

B．connection

C．threat

D．insuranc