向体积为Va的0.05mol•L-1CH3COOH溶液中加入体积为Vb的0.05mol•L-1KOH溶液,下列关系正确的是()
A.Va=Vb时:c (CH3COO-)=c (K+)
B.Va=Vb时:c (CH3COOH)+c (H+)=c (OH-)
C.Va>Vb时:c (CH3COO-)>c (K+)>c (OH-)>c (H+)
D.Va与Vb任意比时:c (K+)+c (H+)=c (OH-)+c (CH3COO-)