This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Medicine
[{'content': 'Gold standard investigation for diagnosis of insulinoma - \nSelect and explain. \nA. Blood glucose level less than 30 mg%, B. 72 hrs fasting, C. C peptide levels less than 32 rjm, D. Serum insulin levels', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Pathology of pancreatic endocrine tumor (insulinoma). Specialty. Oncology. An insulinoma is a tumor of the pancreas that is derived from beta cells and secretes insulin. It is a rare form of a neuroendocrine tumor The diagnosis of insulinoma is suspected in a patient with symptomatic fasting hypoglycemia. The conditions of Whipple\'s triad need to be met for the diagnosis of "true hypoglycemia" to be made: symptoms and signs of hypoglycemia, concomitant p 72 hrs fasting blood glucose level of 45 mg/dL (2.5 mmol/L) or less, and reversibility of symptoms with administration of glucose. Ref Davidson edition23rd pg834', 'role': 'assistant'}]