29. Acetic acid is an electrolyte. Which of the following facts indicate that acetic acidis a weak electrolyte?①Acetic acid and water are miscible in any ratio.
②Acetic acid solution conducts electricity.
③Acetic acid molecules are present in acetic acid solution.
④The pH of 0.1 M acetic acid solution is greater than that of 0.1 M hydrochloricacid.
⑤Acetic acid reacts with calcium carbonate to give off CO2.
⑥The pH of 0.1 M sodium acetate solution = 8.9.
⑦When zinc grains of the same size react with the same concentration ofhydrochloric acid and acetic acid solution, the acetic acid starts to produce H, ata slower rate.
(A)②⑥⑦
(B)③④⑤⑥
(C)③④⑥⑦ 
(D)②④⑥⑦
(E)①②