Which food suggestion would be most appropriate for the mother of a preschooler to ensure an adequate intake of calcium?

The correct answer is B: White beans. White beans are a good source of calcium, which is essential for bone health in preschoolers. They provide a significant amount of calcium per serving compared to the other options. Enriched bread, fortified cereal, and spinach do not contain as much calcium as white beans. Enriched bread and fortified cereal may have added nutrients, but they are not primary sources of calcium. Spinach, although a healthy vegetable, contains oxalates that can inhibit calcium absorption. Therefore, white beans are the most appropriate choice to ensure an adequate intake of calcium for the mother of a preschooler.