A. Apply an external fetal monitor. Applying an external fetal monitor is the appropriate action because it allows continuous monitoring of the fetal heart rate and uterine activity without disturbing the placenta, which is important in cases of placenta previa. B. Complete a vaginal exam. Performing a vaginal exam is contraindicated in cases of suspected placenta previa because it could lead to placental disruption and severe bleeding. The cervix should not be manipulated when placenta previa is suspected. C. Perform a rectal exam. A rectal exam is not indicated for placenta previa and offers no benefit in this context. This action could also increase discomfort and possibly exacerbate bleeding. D. Apply ice to the perineal area. Ice to the perineal area is not relevant for placenta previa. Ice is typically used for perineal trauma or swelling, which is not related to this condition.