In an Aqueous Solution, [H₃O⁺] Is 1

Multiple Choice

In an aqueous solution, [H₃O⁺] is 1.0 × 10⁻⁶ M. What is [OH⁻]?

A) 1.0 × 10⁻⁹ M
B) 1.0 × 10⁻⁸ M
C) 1.0 × 10⁻⁶ M
D) 1.0 × 10⁸ M