Concept:Vitamin A is obtained from foods rich in preformed retinol and provitamin A carotenoids such as β-carotene.Explanation:Egg yolk contains preformed vitamin A, which the body can use directly. Carrots are rich in β-carotene, which the body converts into vitamin A. Palm oil is also a major plant source of β-carotene and vitamin A. These three foods together are major sources of vitamin A, while the combinations in the other options are less reliable or incomplete.Answer:A. egg yolk, carrot and palm oil