The Following Pictures Represent Solutions That Contain a Weak Acid

Multiple Choice

The following pictures represent solutions that contain a weak acid HA (pK_a = 5.0) and its potassium salt KA.Unshaded spheres represent H atoms,black spheres represent oxygen atoms,and shaded spheres represent A^- ions.(K⁺,H₃O⁺ initially present,OH^- initially present and solvent water molecules have been omitted for clarity. )
-Which picture represents the equilibrium state of the solution after addition of one OH^- ion to the solution shown in picture (1) ?

A) (2)
B) (3)
C) (4)
D) (5)