— Why didn't you ask Jim to join us?

— It's between you and me. We must _____ anyone else from knowing our plans. [ ]

A. have

B. allow

C. keep

D. hear

需要建立状态表的防火墙类型是（）

A.包过滤

B.应用代理

C.完全内容检测

D.上述都不对，应该是状态检测防火墙