Which of the Following Will Have the Smallest PH Change

Which of the following will have the smallest pH change upon the addition of 0.001 mole strong acid?

A) 50 mL of a total concentration of 0.10 M pH = 5.2 acetate buffer
B) 100 mL of a total concentration of 0.050 M pH = 5.2 acetate buffer
C) 75 mL of a total concentration of 0.067 M pH = 5.2 acetate buffer
D) 250 mL of a total concentration of 0.020 M pH = 5.2 acetate buffer
E) 25 ml of total concentration of 0.20 M pH = 5.2 acetate buffer