<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 25-year-old woman presents to the emergency department with sudden onset of lower limb weakness for the past 2 days. She says she also hasnt been able to urinate for that same period. There is no history of trauma, fever, weight loss, recent respiratory tract infection, or diarrhea. She has a past medical history of left arm weakness 18 months ago that resolved spontaneously. Her father had type 2 diabetes mellitus, ischemic heart disease, and left-sided residual weakness secondary to an ischemic stroke involving the right middle cerebral artery. Her vital signs include: blood pressure 12089 mm Hg, temperature 36.7C 98.0F, pulse 78min, and respiration rate 16min. Muscle strength is 35 in both lower limbs with increased tone and exaggerated deep tendon reflexes. The sensation is decreased up to the level of the umbilicus. Muscle strength, tone, and deep tendon reflexes in the upper limbs are normal. On flexion of the neck, the patient experiences electric shock-like sensations that travel down to the spine. Funduscopic examination reveals mildly swollen optic discs bilaterally. Which of the following is the next best step in management for this patient?? A: Interferon beta, B: Intravenous immunoglobulin, C: Intravenous methylprednisolone, D: Plasmapheresis, E: Riluzole,  <response>: This is a clinical vignette describing a 25-year-old woman with acute onset lower extremity weakness, urinary retention, and sensory level concerning for a spinal cord lesion. Key findings include bilateral lower extremity weakness, hyperreflexia, upgoing toes, sensory level, and Lhermittes sign concerning for demyelinating disease like multiple sclerosis. The history of a previous episode of unilateral weakness that resolved spontaneously also supports relapsing-remitting MS. The choices listed are disease-modifying therapies for MS.C: Intravenous methylprednisolone 