$1.$ Addressing$$Consider the network $210\mathrm{.}4\mathrm{.}2\mathrm{.}0,$ and answer the following: $(20\%)$

a$.$ According to IPv$4,$ which class of network is this? Explain. $(5\%)$

According to IPv$4,$ the network $210\mathrm{.}4\mathrm{.}2\mathrm{.}0$ belongs to Class C because the first octet of the given address is $210,$ which falls within the range $192-223$ for Class C$.$

b$.$ Host $210\mathrm{.}4\mathrm{.}2\mathrm{.}80$ belongs to a subnet containing the second group of $64$ addresses in this network. Show the subnet address and subnet mask associated with this host. $(5\%)$

$2.$