The network topology given in Figure Q$3$ has the network address of $200\mathrm{.}20\mathrm{.}20\mathrm{.}0/24.$

Apply an IPv$4$ addressing scheme using Variable Length Subnet Mask $($VLSM$)$ to the network. Your scheme should conserve as many IP addresses as possible. You are to use the next available subnet to subnet further. Illustrate your scheme by completing the following tasks.

$($a$)$ Assign appropriate subnet addresses to all the Local Area Networks $($LANs$)$ and Wide Area Networks $($WANs$).$

Use the format given in Table Q$3$ to tabulate your workings for Q$3($a$).$ The table shows a sample entry.

$($b$)$ Derive the entire range of useable host IP addresses for all the LANs. Show your working.