A's breakfast lacks protein and vitamins; B's breakfast contains protein, fat, water, minerals and vitamins, but it lacks sugar, the main energy source. C's breakfast contains sugar, protein, fat, vitamins, water and minerals, and C's nutrition is comprehensive and moderate. Suggestion A: Remove a pineapple bag, add an egg and replace Fanta with carrot juice. Suggest B add a breakfast bread and half an apple.

So the answer is: A's breakfast lacks protein and vitamins; B's breakfast contains protein, fat, water, minerals and vitamins, but it lacks sugar, the main energy source. C's breakfast contains sugar, protein, fat, vitamins, water and minerals, and C's nutrition is comprehensive and moderate. Suggestion A: Remove a pineapple bag, add an egg and replace Fanta with carrot juice. Suggest B add a breakfast bread and half an apple.