Buffer solution are used to

Explanation

Buffer solutions are used to resist changes in pH when small amounts of acid or base are added. They do this through a chemical equilibrium between a weak acid and its conjugate base (or a weak base and its conjugate acid). The correct answer, therefore, is to 'Resist changes in pH', as buffer solutions do not inherently increase or decrease pH, but rather maintain it within a narrow range. Options A and B are incorrect because buffers do not serve to increase or decrease pH outside of small adjustments to maintain equilibrium. Option D is incorrect because option C correctly describes the function of a buffer solution.