In Water, the Following Equilibrium Exists: in Pure Water $\degree$

In water, the following equilibrium exists: In pure water at 25 $\degree$ C, the concentration of H⁺ ions is 1.00 * 10¯⁷ mol/L. Calculate the value of the equilibrium constant for the reaction as written above.

A) 1.00 *10¹⁴
B) 1.00 * 10¹²
C) 1.00 * 10¯¹⁴
D) 1.00 * 10¯¹²
E) 5.55 * 10¹⁵