According to the current (2005) Dietary Guidelines for Americans:

The opposite is true - adults over 50 have reduced vitamin B12 absorption due to declining gastric acid secretion and intrinsic factor production, making deficiency more, not less, likely with age.

Heme iron from animal sources is substantially more bioavailable (15-35% absorption rate) than non-heme iron from plant sources (2-20%), so animal sources are the richer functional iron source, not plant sources.

While the guidelines do address folic acid for women of childbearing age, this is a general recommendation rather than a specific risk-group finding; the guidelines highlight vitamin D deficiency as a distinct concern for the populations named in option D.

Aging reduces the skin's capacity to synthesize vitamin D3 from UVB radiation because of decreased 7-dehydrocholesterol concentrations in aged skin. Individuals with darker skin have higher melanin content, which acts as a natural filter and significantly reduces UVB penetration - both mechanisms independently impair cutaneous vitamin D production, placing both groups at elevated risk per the 2005 Guidelines.