多项选择题 A national retail chain needs to design an IP addressing scheme to support a nationwide network. The company needs a minimum of 300 sub-networks and a maximum of 50 host addresses per subnet. Working with only one Class B address, which of the following subnet masks will support an appropriate addressing scheme?（）

多项选择题 Which three are characteristics of an IPV6 anycast address?（）

单项选择题 Which option is a valid IPv6 address?（）