What is the $pH$ of pure water at $40\mathrm{.}0C$ if the $K_W$ at this temperature is $2\mathrm{.}92{10}^{-14}$

A$)7\mathrm{.}233$

B$)6\mathrm{.}767$

C$)8\mathrm{.}446$

D$)0\mathrm{.}465$