The Following Figure Illustrates the Action of a HF and F

Multiple Choice

The following figure illustrates the action of a HF and F^ buffer where the sizes of the boxes are proportional to the concentrations of HF and F^ in solution. According to this figure, what happens when H₃O⁺ is added to the HF/F^ buffer?

A) The pH decreases.
B) The pH increases.
C) The concentration of HF increases.
D) The concentration of F^ increases.
E) Nothing happens.