从H₂O₂溶液制氧气的残余物中分离出MnO₂可采用的实验操作是______（填操作名称）；除去氯化钠溶液中的硫酸钠可向其中加入适量的______（填化学式）溶液．

NAC’s (Network Access Control) role is to restrict network access to only compliant endpoints and（）users. However, NAC is not a complete LAN（）solution; additional proactive and（）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（）. In addition to NAC, enterprises need to implement role-based network access control as well as critical proactive security measures — real-time, multilevel（）inspection and microsecond threat containment.

Nevis integrates NAC as the first line of LAN security（）.

A．defense

B．intrusion

C．inbreak

D．protection