You are answering a USMLE-style medical question. Question: A 24-year-old woman presents to the emergency department after an episode of altered mental status. She was at a party when she suddenly fell to the floor. Her friends state that she was not responsive and was acting oddly. After the episode, the patient seemed confused and had no memory of the event. The patient has a past medical history of substance abuse, depression, and anxiety. Her temperature is 98.6°F (37.0°C), blood pressure is 117/69 mmHg, pulse is 80/min, respirations are 12/min, and oxygen saturation is 99% on room air. Physical exam reveals a girl who seems confused and responds to questions slowly. Her gait is stable, and she demonstrates 5/5 strength in her upper and lower extremities. Laboratory values and a urine dipstick test are performed as seen below: Toxicology: Benzodiazepines: Positive Marijuana: Positive Cocaine: Negative Phencyclidine: Negative Urine Dipstick: Appearance: Dark Red blood cells: Positive Glucose: Negative Which of the following is the best next step in management? Options: A) Diazepam B) IV fluids and mannitol C) Phenytoin D) Supportive therapy and observation Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.