Which of These Statements Concerning PH Is Incorrect

Which of these statements concerning pH is incorrect ?

A) pH is based on the [H₃O⁺] in solution.
B) If [H₃O⁺] = 1.0 × 10 ^{− 13}, the solution is basic.
C) pH = 3 is ten times more acidic than pH = 2.
D) If pH > 7, the solution is basic.
E) Pure water has [H₃O⁺] = 1.0 × 10 ^{− 7}.