Answer
The correct option is (c): The pH will not change.
Work Step by Step
A buffer is a combination of chemicals that do not alter the pH. The constant pH level is maintained by accepting excess hydrogen or hydroxyl ions. In living systems, the pH of body fluids maintains the narrow range. The pH of blood is always 7.4 and is slightly basic. Therefore, the addition of acid to a buffered solution will not affect its pH.
As there is a buffer in the media to negate any change in pH. pH of the solution, therefore, remains same. hence option a and b are incorrect while c is the correct choice.