[单选题]38、 Which of the following are available interface types that can be used for a stateful failover link between peers?下面哪些接口类型可用于对等设备之间的基于状态的状态切换链路?
A. Any unused physical interface 任何未使用的物理接口
B. The existing failover interface 现有的故障切换接口
C. An existing -network interface 现有的网络结构
D. All of the above 所有上述接口