参考答案: AD
详细解析:
由题可知，AC为dhcp中继设备，dhcp中继设备需要配置dhcp relay功能，并且绑定dhcp的服务器IP（172.21.1.2）。AP设备为dhcp服务器，需要配置dhcp地址池，地址池应该为AP所需要获取的ip网段（10.1.1.0/24），并且在接口配置dhcp功能选择全局地址池。
因此答案选AD。
如图所示，LAN的管理VLAN是VLAN 10，AP通过DHCP获取IP地址，网段为10.1.1.0/24 ，AP、AC和AR分别为DHCP的客户端、DHCP中继设备以及DHCP服务器。以下关于DHCP中继设备以及DHCP服务器配置正确的是?
A. [AC]dhcp server group AP[AC-dhcp-server-group-AP] dhcp-server 172.21.1.2[AC-dhcp-server-group-AP] quit [AC]interface Vlanif 10 [AC-Vlanif10]dhcp select relay[AC-Vlanif10] dhcp relay server-select AP[AC-Vlanif10] quit
B. [AR] ip pool AP[AR-ip-pool-AP] network 172.21.1.0 mask 24[AR-ip-pool-AP]gateway-list 172.21.1.2 [AR-ip-pool-AP]excluded-ip-address 172.21.1.1[AR-ip-pool-AP] quit[AR] interface GigabitEthernet 0/0/1 LAR-GigabitEthernet0/0/1] dhcp select global[AR-GigabitEthernet0/0/1 ]quit[AR]ip route-static 10.1.1.0 255.255.255.0 172.21.1.1
C. [Ac]dhcp server group AP[AC-dhcp-server-group-AP] dhep-server 10.1.1.2 [AC-dhcp server group-AP] quit [AC] interface vlanif 10[Ac-Vlanif10] dhcp select relay[AC-Vlanif10]dhcp relay server-select AP[AC-Vlanif10]quit
D. [AR] ip pool AP[AR-ip pool-AP] network10.1.1.0 mask 24[AR-ip-pool-AP] gateway-list 10.1.1.2 [AR-ip-pool-AP]excluded ip-address 10.1.1.1[AR-ip-pool-AP]quit [AR] interface GigabitE thernet 0/0/1[AR-GigabitEthernet0/0/1] dhcp selectglobal [AR-GigabitEthernet0/0/1] quit[AR] ip route-static 10.1.1.0 255.255.255.0 172.21.1.1