1. [单选题]On the topic of VLSM, which one of the following statements best describes the concept of the route aggregation?
A. Deleting unusable addresses through the creation of many subnets.
B. Combining routes to multiple networks into one supernet.
C. Reclaiming unused space by means of changing the subnet size.
D. Calculating the available host addresses in the AS.
E. None of the above
2. [单选题]当在一个接口上使用ipaccess-group99in命令时，以下哪条关于所引用访问控制列表的描述是正确的（）
A. 这个列表是编号型扩展ACL，检查离开接口的数据包
B. 这个列表是命名的扩展ACL，检查进入接口的数据包
C. 这个列表是编号型标准ACL，检查进入接口的数据包
D. 这个列表是命名的标准ACL，检查离开接口的数据包
3. [单选题]Assuming you build networks to exact specifications, what is the recommended maximum length a 10BaseT cable can be before it has to be segmented or repeated?
A. 100 meters
B. 100 feet
C. 100 yards
D. 200 meters
E. None of the above
