In a network with sub$-$netting the sub$-$net mask is $255\mathrm{.}255\mathrm{.}248\mathrm{.}0.$ If the IP address is

$37\mathrm{.}125\mathrm{.}163\mathrm{.}129,$ the hostid part is:

$[$A$]01110000001$

$[$B$],01010000001$

$[$C$]10010000001$

$[$D$],11010000001$