If the pH of a solution is decreased from 7 to 6, it means that the
A. concentration of H+ has decreased to 10 times of what it was at pH 7.
B. concentration of H+ has increased to 10 times of what it was a pH 7.
C. concentration of OH- has increased to 10 times what it was at pH 7.
D. concentration of OH- has decreased to 10 times what it was at pH 7.
E. Both B and D are correct.
Answer: E