Q$2.$ Consider a subnet with prefix $168\mathrm{.}0\mathrm{.}0\mathrm{.}64/27.$

$($a$)$ Give the range of IP addresses $($of form xxx$.$xxx$.$xxx$.$xxx$)$ that can be assigned to for valid hosts in this network.

$($b$)$ Suppose an ISP owns the block of addresses of the form $168\mathrm{.}0\mathrm{.}0\mathrm{.}64/27.$ Suppose it wants to create four subnets from this block, with each block having the same number of IP addresses. What are the prefixes $($of form a$.$b$.$c$.$d$/$x$)$ for the four subnets?