A primigravida client at 36-weeks gestation is admitted to the labor and delivery unit because her membranes ruptured 30 minutes ago. Initial assessment indicates a 2 cm cervical dilatation, 50% effaced, -2 station, vertex presentation, greenish-colored amniotic fluid, and contractions occurring every 3 to 5 minutes, with a decrease in fetal heart rate after the last four contraction peaks. Which action should the nurse implement first?

A. Administer oxygen via face mask. The decrease in fetal heart rate after contractions indicates possible fetal distress. Administering oxygen to the mother can increase oxygen delivery to the fetus, potentially improving fetal oxygenation and alleviating distress. B. Apply an Internal fetal heart monitor. While continuous monitoring is important, the first priority is to address the immediate fetal distress. Monitoring alone will not address the issue. C. Notify the healthcare provider. Notifying the provider is important, but addressing the immediate fetal distress takes priority. D. Use a vibroacoustic stimulator. Vibroacoustic stimulation can be used to assess fetal well- being, but it does not address the underlying fetal distress, which is the priority.