<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 53-year-old man is brought to the emergency department by his wife for the evaluation of a progressively generalized headache that started suddenly 2 hours ago. He describes the pain as 10 out of 10 in intensity. The pain radiates to the neck and is aggravated by lying down. The patient has vomited once on his way to the hospital. He had a similar headache 1 week ago that had resolved after a few hours without treatment. The patient has smoked one pack of cigarettes daily for 35 years. He does not drink alcohol or use illicit drugs. He appears lethargic. His temperature is 37.7C 99.9F, pulse is 82min, respirations are 13min, and blood pressure is 16589 mm Hg. Pupils are equal and reactive to light and extraocular eye movements are normal. There is no weakness or sensory loss. Reflexes are 2 throughout. Neck flexion causes worsening of the pain. Which of the following is the most appropriate next step in the management of this patient?? A: Electroencephalogram, B: Lumbar puncture, C: MRI scan of the brain, D: CT angiography of the head, E: CT scan of the head without contrast,  <response>: This is a patient with an acute, severe headache that started suddenly 2 hours ago. The headache is worse when lying down and with neck flexion, suggesting meningeal irritation. The patient had a similar headache 1 week ago that resolved spontaneously. Key findings on exam include nauseavomiting, lethargy, and elevated blood pressure. The differential diagnosis includes subarachnoid hemorrhage, meningitis, migraine headache, and hypertension. Imaging of the brain is needed to evaluate for bleed or mass lesion. Lumbar puncture should be deferred until imaging is completed due to risk of brain herniation if there is mass effect from hemorrhage or tumor. MRI is more sensitive than CT for identifying structural lesions but takes longer to perform. CT angiography could identify vascular abnormalities but CT head without contrast is faster and would identify hemorrhage or mass effect.E: CT scan of the head without contrast 