Which of the following is not a valid subnet mask?

Question $5$ options:

$255\mathrm{.}230\mathrm{.}0\mathrm{.}0$

$255\mathrm{.}224\mathrm{.}0\mathrm{.}0$

All of the given options are valid subnet mask

$255\mathrm{.}255\mathrm{.}192\mathrm{.}0$

$255\mathrm{.}192\mathrm{.}0\mathrm{.}0$