The Following Pictures Represent Solutions That Contain a Weak Acid

Multiple Choice

The following pictures represent solutions that contain a weak acid HA and/or its potassium salt KA.Unshaded spheres represent H atoms and shaded spheres represent A^- ions.(K⁺,H₃O⁺,OH^-,and solvent H₂O molecules have been omitted for clarity. )
-Which of the solutions are buffer solutions?

A) (1) and (2)
B) (1) and (3)
C) (2) and (3)
D) (2) and (4)