Which of the following has correct Subnet Mask?

$(3$pts$)$

Question $3-$ Which of the following has correct Subnet Mask?

$255\mathrm{.}255\mathrm{.}255\mathrm{.}125$

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

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

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

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