Final answer:
In the case of an umbilical cord prolapse during labor, the mother should be positioned with elevated hips, given oxygen, and transported promptly for medical intervention.
Step-by-step explanation:
The correct response to a situation where a 25-year-old woman in active labor presents with the umbilical cord protruding through the vagina is d) Place the mother in a supine position with the hips elevated, administer oxygen, and transport. This is an obstetric emergency known as umbilical cord prolapse, and it requires immediate medical intervention to reduce the risk of fetal hypoxia and possible death. Gently pulling on the cord or massaging the uterus could be harmful and are contraindicated. The priority is to relieve pressure on the cord, hence elevating the hips (Trendelenburg position) helps keep the baby from compressing it, while preparing for an urgent delivery, often by cesarean section.