From the diagram in the question, we know: Foods C and D have the highest content of iron-containing inorganic salts, while foods A and B have very low contents; Food B has the highest content of calcium-containing inorganic salts; The content of vitamin C is higher in food B; the content of vitamin D is highest in food A. The content of calcium-containing inorganic salts and vitamin D in food D is not very high. If food D is the staple food for a long time, it will lead to rickets.

So choose: D