Answer:A
Explanation:
Buffers are molecules that resist fluctuations in pH by donating or accepting electrons with the introduction of more acids or bases to a solution.
Their general function in all living organisms is to maintain relatively constant blood plasma pH for effective biochemical reactions.
In living cells examples are;
Carbonic acid bicarbonate; buffer system to neutralise elevated hydrogen ion from high blood carbon dioxide
Protein buffer system; mopping of excess hydrogen ions by haemoglobin
Phosphate buffer system ;, for neutralisation of excess hydrogen ions by releases of hydrogen phosphate ions
Therefore A is odd.