Which of the Following Solutions Would Be the Best Buffer

Multiple Choice

Which of the following solutions would be the best buffer capable of resisting change in pH when a small amount of NaOH is added to the solution?

A) a 1.0 L solution prepared by adding 0.10 mol of carbonic acid and 0.10 mol of sodium bicarbonate
B) a 1.0 L solution prepared by adding 0.20 mol of carbonic acid and 0.20 mol of sodium bicarbonate
C) a 1.0 L solution prepared by adding 0.10 mol of hydrochloric acid and 0.10 mol of sodium hydroxide
D) a 1.0 L solution prepared by adding 0.20 mol of hydrochloric acid and 0.20 mol of sodium hydroxide
E) All of these solutions would have the same buffer capacity.