NAC’s (Network Access Control) role is to

问题：

NAC’s (Network Access Control) role is to restrict network access to only compliant endpoints and (66) users. However, NAC is not a complete LAN (67) solution; additional proactive and (68) security measures must be implemented. Nevis is the first and only comprehensive LAN security solution that combines deep security processing of every packet at 100Gbps, ensuring a high level of security plus application availability and performance. Nevis integrates NAC as the first line of LAN security (69) In addition to NAC, enterprises need to implement role-based network access control as well as critical proactive security measures-real-time, multilevel (70) inspection and microsecond threat containment.

（70）是（）

A.port

B.connection

C.threat

D.insurance