What Is the [H₃O⁺] in a Solution That Consists of 1.2

What is the [H₃O⁺] in a solution that consists of 1.2 M HClO and 2.3 M NaClO? K_a = 3.5 × 10⁻⁸

A) 7.8 × 10 ⁻⁹ M
B) 1.8 × 10 ⁻⁸ M
C) 6.7 × 10 ⁻⁸ M
D) 1.6 × 10 ⁻⁷ M
E) None of these choices are correct.