Which of the Following Is True

Multiple Choice

Which of the following is true?

A) The pH of a solution where the A− to HA ratio is 1 has a pH = pK_a.
B) If the pH does not equal the pK_a, the solution is not a buffer.
C) The best buffer for any experiment will always have a pH equal to the pK_a.
D) If a buffer has more weak acid than conjugate base, the pH will be higher than the pK_a.