Borrow three bits from the network address $192\mathrm{.}168\mathrm{.}15\mathrm{.}0$ and determine the following:

a$.$ subnet mask in binary and in dotted decimal

b$.$ value of the binary bits used to identify the third useable subnet

c$.$ the binary bits in the host region used to identify the first useable host

d$.$ the binary bits in the host region used to identify the last useable host

e$.$ the third subnet's network address in binary and dotted decimal

f$.$ the fifth subnet's network broadcast address

g$.$ the last useable host address in binary and dotted decimal for the sixth useable subnet