You are answering a USMLE-style medical question. Question: A 25-year-old woman presents generalized abdominal pain and vomiting for the past hour. She has also had watery diarrhea for several days with no blood or pus in the stools. She is taking an over-the-counter anti-diarrheal medication, which she cannot remember the name of, and drinking oral rehydration solution, which has helped a little. Her past medical history shows she was hospitalized 10 years ago for an appendectomy and 4 years ago for a fractured ulna following a motor vehicle accident. Vital signs are pulse is 104/min, blood pressure is 120/80 mm Hg, respiratory rate of 14/min with shallow breathing, and temperature is 36.7°C (98.0°F). On physical examination, pupils are constricted. Extremities are pale and cold. The abdomen is soft but mildly, diffusely tender to palpation with a palpable bladder. No rebound or guarding. Fingerstick blood glucose is 124 mg/dL. Laboratory tests are pending. A urinary catheter is placed, and intravenous fluids are started. Abdominal imaging shows no abnormalities. Which of the following is the next best step in the management of this patient? Options: A) Administer naloxone B) Scopolamine patch C) Start dextrose infusion D) Perform a gastric lavage Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.