Final answer:
In the emergency where a nurse discovers an umbilical cord prolapse during labor, the correct action is to elevate the client's hips and call for assistance to prevent fetal distress or serious complications.
Step-by-step explanation:
The subject of the question involves a critical labor and delivery scenario, known as umbilical cord prolapse, which requires immediate medical attention. When a nurse performing a vaginal assessment during active labor notices that the umbilical cord is protruding from the vagina, the correct immediate response is to elevate the client's hips and call for assistance (option c). This emergency situation can compromise blood flow to the baby and requires urgent intervention to prevent fetal distress or other serious complications. Inserting a urinary catheter is not pertinent for this scenario, and instructing the client to push could exacerbate the prolapse, hence these options (b and d) are not correct. Applying gentle pressure to the presenting part (option a) is also incorrect, as it may worsen the umbilical cord compression.