[单选题]10、 Of the available HA and load-balancing methods, which one from the following choices requires matching hardware and software on each device?在可用HA和负载平衡的方法中，下面哪一个选择需要每个设备上都必须具有相同的硬件和软件?
A. Clustering 集群
B. VPN load balancing VPN负载平衡
C. Active/standby failover active/standby故障切换
D. Redundant peering 冗余对等体