单项选择题 How many subnetworks and hosts are available per subnet if you apply a /28 mask to the 210.10.2.0 class C network?（）

单项选择题 You have a Class C network, and you need ten subnets. You wish to have as many addresses available for hosts as possible. Which one of the following subnet masks should you use?（）

多项选择题 Which two of the addresses below are available for host addresses on the subnet 192.168.15.19/28?（）