Evaluate the following statements about women’s health:

1. Endometriosis involves the growth of uterine tissue outside the uterus.
2. Polycystic ovary syndrome (PCOS) is associated with irregular menstrual cycles and insulin resistance.
3. Preeclampsia during pregnancy is characterized by hypertension and proteinuria after 20 weeks of gestation.
4. Vaginal yeast infections are most commonly caused by Escherichia coli.

Which of the following options correctly identifies the true statements?