What is the most likely source of these circulating estrogens in a 54-year-old G4P4 who has been menopausal for four years and has never had any menopausal symptoms?
1) Exogenous dietary intake
2) Limited adrenal estrogen secretion
3) Lingering ovarian estrogen
4) Aromatization of circulating androgens
5) Continued low-level ovarian production