A pregnant woman's diet may not meet her need for folates. A good source of this nutrient is:

Choice A reason: This is incorrect because primary dysmenorrhea is menstrual pain that is not associated with any underlying condition. It usually begins with the onset of menstruation and lasts for a few days. It does not cause pain during intercourse or infertility.

Choice B reason: This is correct because endometriosis is a condition where the endometrial tissue that normally lines the uterus grows outside the uterus, such as on the ovaries, fallopian tubes, or pelvic organs. It causes chronic inflammation, scarring, and adhesions that can result in severe pain during menstruation and intercourse, as well as infertility.

Choice C reason: This is incorrect because secondary dysmenorrhea is menstrual pain that is caused by an underlying condition, such as fibroids, pelvic inflammatory disease, or adenomyosis. It usually develops later in life and lasts longer than primary dysmenorrhea. It may or may not cause pain during intercourse or infertility, depending on the condition.

Choice D reason: This is incorrect because PMS stands for premenstrual syndrome, which is a group of physical and emotional symptoms that occur before menstruation. It may include mood swings, irritability, bloating, headaches, or breast tenderness. It does not cause severe pain during menstruation or intercourse, or infertility.

Choice A reason: Cheese is a good source of calcium, protein, and vitamin B12, but not folates. Folate is a water-soluble vitamin that is essential for the synthesis of DNA and the prevention of neural tube defects in the fetus.

Choice B reason: Potatoes are a good source of carbohydrates, potassium, and vitamin C, but not folates. Folate is found mainly in plant-based foods, especially dark green vegetables.

Choice C reason: Chicken is a good source of protein, iron, and zinc, but not folates. Folate is more abundant in legumes, nuts, and seeds than in animal products.

Choice D reason: Green leafy vegetables are a good source of folates, as well as vitamin A, vitamin K, and fiber. Folate is also known as folic acid when it is added to fortified foods or supplements. Pregnant women need at least 600 micrograms of folate per day.