问题
单项选择题
There is free firewall software available that can run on minimal hardware and provide a good level of (71) to your network.
A. protective
B. profecting
C. protection
D. profection
答案
参考答案：C
解析： 免费的防火墙可以安装在很小的硬件上，对计算机网络提供高水平的保护。
