$5.-$ Subnetting $[20$ points$]$

a$.$ How does subnetting help in making better use of the available IP address space?

b$.$ Your organization has obtained a network address of $129\mathrm{.}244\mathrm{.}0\mathrm{.}0/16$ and they have a need to break it down into at least five subnets $($do not use more bits than needed for those subnets$).$

c$.$ What is the maximum number of hosts you could support in each subnet?

d$.$ Calculate the subnet mask.

c$.$ Give the valid IP address range of the fifth usable subnet address.