多项选择题 Given the address 192.168.20.19/28, which of the following are valid host addresses on this subnet?（）

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 Use the output from the router shown in the graphic above to determine which of the following are correct.（）