Final answer:
The nurse should notify the healthcare provider immediately if amniotic fluid is stained greenish-black, indicating the baby has passed meconium, which requires prompt aspiration from the newborn to prevent inhalation.
Step-by-step explanation:
When amniotic fluid is stained greenish-black during childbirth, it indicates that the newborn has passed meconium in utero. This can be a sign of fetal distress, and it is important for healthcare providers to act promptly to reduce the risk of meconium aspiration syndrome. The appropriate intervention in this case is B. Notify the healthcare provider. It is critical that meconium is aspirated from the newborn before the first breath to prevent inhalation into the lungs which can lead to serious complications.