A. Administering methylergonovine (Methergine) intramuscularly is appropriate for treating postpartum hemorrhage, as it stimulates uterine contractions to help control bleeding. B. The knee-chest position is not indicated for postpartum hemorrhage and does not address the underlying cause. C. Oxygen may be necessary if the client is unstable, but 2 L/min via nasal cannula is not the primary intervention and may not be sufficient in a critical situation. D. Dextrose water is not appropriate for fluid resuscitation during hemorrhage; isotonic fluids like normal saline or lactated Ringer’s are preferred to restore volume.