For every network find the subnet mask and the range of IPs that can be assigned to hosts: a$.16\mathrm{.}30\mathrm{.}0\mathrm{.}0/20$b$.180\mathrm{.}5\mathrm{.}4\mathrm{.}0/26$c$.120\mathrm{.}30\mathrm{.}192\mathrm{.}0/22$