When 10 X 10^-5 Mole of HOCl (K_a = 3

When 1.0 x 10^-5 mole of HOCl (K_a = 3.5 x 10^-8) is dissolved in pure water and diluted to 1.00 L, which assumption can't be applied in the calculation of the pH of this solution?

A) that the initial concentration of HOCl is much larger than the total H₃O⁺ ion concentration
B) that the H₃O⁺ ion concentration from the dissociation of water can be ignored.
C) that the total H₃O⁺ ion concentration is the sum of the concentrations from the dissociation of HOCl and water
D) all of these assumptions are valid
E) none of these assumptions are valid