At 10°C,the Ion-Product Constant of Water,K_w,is 6

At 10°C,the ion-product constant of water,K_w,is 6.88 × 10^-15.What is the pH of pure water at 10°C?

A) 7.000
B) 6.684
C) 7.364
D) 7.264
E) none of these