A nurse is providing teaching to a group of clients about risk factors for ovarian cancer.Which of the following risk factors should the nurse include? (Select all that apply.)

Choice A rationaleNulliparity increases ovarian cancer risk by prolonging ovulation periods. Continuous ovulation raises the likelihood of genetic mutations in ovarian epithelial cells.Choice B rationaleBreastfeeding lowers ovarian cancer risk by suppressing ovulation through hormonal regulation during lactation. This protective effect decreases cellular mutation opportunities.Choice C rationalePostmenopausal estrogen therapy elevates ovarian cancer risk by stimulating cell proliferation in ovarian tissues, promoting oncogenesis in hormonally sensitive cells.Choice D rationaleOral contraceptives reduce ovarian cancer risk by suppressing ovulation and stabilizing hormonal levels, leading to decreased oxidative stress on ovarian epithelium.Choice E rationaleA history of breast cancer correlates with increased ovarian cancer risk due to shared genetic mutations, such as BRCA1/2, which predispose individuals to both malignancies.