Final answer:
Eggs are the best source of vitamin B-12 among the given options, as B-12 is predominantly found in animal products and is essential for various cellular processes.
Step-by-step explanation:
The food that is a good source of vitamin B-12 from the options given is eggs. Vitamin B-12 is essential for various cellular processes and is typically found in foods of animal origin. Meat, liver, fish, chicken, and eggs are all considered rich sources of vitamin B-12. While other foods like cereals, nuts, and certain oils may provide some B vitamins, they are not as potent in vitamin B-12 as animal-derived products. Vegetables, fruits, and whole grains generally contain less or no vitamin B-12, making eggs the best option from the list provided.