The molarity of water is regarded as

Weight of pure water $=1\mathrm{Kg}=1000\mathrm{gm}$
Number of moles of pure water $=$Weight of pure water Gram molecular mass
$=1000$ Molarity
$=\frac{1000}{18}$
$=55.55$ moles
So, the required answer is option B) 55.55