B, mushrooms can't convert inorganic substances into catalytic organic substances, and they can only rely on ready-made organic substances to survive. It is the fault of heterotrophs and B;

C. E.coli can't convert inorganic substances into catalytic organic substances, and can only rely on ready-made organic substances to survive. It is the fault of heterotrophs and C;

D, human immunodeficiency virus can't convert inorganic substances into catalytic organic substances, and can only rely on ready-made organic substances to survive. Heterotrophs is parasitic in living cells, and D is wrong.

So choose: a.