Final answer:
Heme iron found in animal sources such as red meat, poultry, and fish provides the most absorbable iron.
Step-by-step explanation:
The most absorbable iron is heme iron which is found in animal sources such as red meat, poultry, and fish. Heme iron is absorbed more efficiently than non-heme iron from plant sources.
For example:
- 1 cup of milk does not contain heme iron.
- 1 apple does not contain iron.
- 1/2 cup of spinach contains non-heme iron, but it is not as absorbable as heme iron.
Therefore, out of the given options, animal sources like red meat would provide the most absorbable iron.