You have been given a Class B network IP address with which to configure the new network you are designing. Which of the following is the default subnet mask you should use for an IPv$4$ Class B network?

Question $66$ options:

$255\mathrm{.}255\mathrm{.}255\mathrm{.}255$

$255\mathrm{.}255\mathrm{.}255\mathrm{.}0$

$255\mathrm{.}255\mathrm{.}0\mathrm{.}0$

$255\mathrm{.}0\mathrm{.}0\mathrm{.}0$