1. [单选题]IP地址为：192.168.50.70，掩码为：255.255.255.248，则该IP地址所在子网的子网有效IP为（）
A. 192.168.50.33---192.168.50.39
B. 192.168.50.41---192.168.50.50
C. 192.168.50.65---192.168.50.70
D. 192.168.50.66---192.168.50.75
2. [多选题]The Ezonexam network administrator issues the ping 192.168.2.5 command and successfully tests connectivity to a host that has been newly connected to the network. Which protocols were used during the test? (Choose two)
A. ARP
B. CDP
C. DHCP
D. DNS
E. ICMP
