A 55 year old female comes to the emergency department complaining of a headache for the past six hours. Her headache began abruptly after she finished eating breakfast, andquickly increased to 8/10 throbbing pain located mainly over her right temple. The pain has been associated with mild nausea but no vomiting. She denies chronic or recurrentheadaches, but did have one headache similar to this one two weeks ago, which resolved after taking ibuprofen and lying in a quiet, dark room. She has smoked one pack ofcigarettes daily for 38 years. On physical exam, the patient has temperature of 37.0 C (98.6 F), pulse of 99, and BP 147/95. Neurological examination is nonfocal, but mildphotophobia and nuchal rigidity are noted. Fundoscopic examination reveals no papilledema. Skin exam shows no lesions. CT of the head, obtained without contrast, reveals noabnormalities. What is the most appropriate next step in the management of this patient?

A. Obtain head CT with contrast
B. Lumbar puncture
C. Administer i.m. sumatriptan
D. Administer oral ibuprofen
E. Administer i.v. ceftriaxone