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

A. Enriched bread may contain some calcium, but it's not as rich a source as other options. B. White beans are a good source of calcium, which is important for bone health in preschoolers. C. Fortified cereal may contain added calcium, but it may not be as naturally rich as other food sources. D. While spinach contains calcium, it also contains oxalates, which can inhibit calcium absorption, making it a less effective source of dietary calcium.