The correct answer is: B. Remains same.
A buffer solution is a solution that resists changes in pH when small amounts of acids or bases are added to it. This is because a buffer solution contains a mixture of an acid and its conjugate base, or a base and its conjugate acid. When
an acid is added to a buffer solution, the conjugate base of the acid reacts with the acid to form more of the original acid. This prevents the pH of the solution from decreasing. When a base is added to a buffer solution, the conjugate acid of the base reacts with the base to form more of the original base. This prevents the pH of the solution from increasing.The pH of a buffer solution is determined by the ratio of the concentrations of the acid and its conjugate base, or the base and its conjugate acid. The pH of a buffer solution is not affected by the volume of the solution. Therefore, if a buffer solution is diluted, the pH of the solution will remain the same.
Option A is incorrect because the pH of a buffer solution is not increased when the solution is diluted. Option C is incorrect because the pH of a buffer solution is not decreased when the solution is diluted. Option D is incorrect because the pH of a buffer solution does not slowly increase and then decrease when the solution is diluted.