<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 23-year-old woman is seen by her primary care physician. The patient has a several year history of excessive daytime sleepiness. She also reports episodes where she suddenly falls to the floor after her knees become weak, often during a laughing spell. She has no other significant past medical history. Her primary care physician refers her for a sleep study, which confirms the suspected diagnosis. Which of the following laboratory findings would also be expected in this patient?? A: Increased serum methoxyhemoglobin, B: Reduced serum hemoglobin, C: Undetectable CSF hypocretin-1, D: Increased CSF oligoclonal bands, E: Increased serum ESR,  <response>: This is a clinical vignette describing a patient with excessive daytime sleepiness and episodes of sudden weakness in the knees and falling, often triggered by laughing. The history and sleep study are consistent with narcolepsy. In narcolepsy, there is loss of hypocretin orexin producing neurons in the hypothalamus. Hypocretin is measured in the CSF, so reduced or undetectable levels would be expected in this patient.C: Undetectable CSF hypocretin-1 