Protein is the basic substance that constitutes human cells. The growth and development of human body and the renewal and repair of cells are inseparable from protein. In addition, protein can be decomposed to provide energy for human physiological activities. The human body needs few inorganic salts, but they play a great role. For example, calcium in inorganic salts is the main substance that constitutes teeth and bones, especially calcium deficiency in adolescents can easily lead to rickets. Therefore, growing teenagers should eat more foods containing protein and various inorganic salts, which are II and III in the picture.

So choose: B.