This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pancreas, Subject name: Surgery
[{'content': 'A 64-year-old man complains of abdominal pain, pruritus, 4-lb weight loss, and anorexia. There are multiple scratch marks on the skin of the extremities and flank. The bilirubin is 1.0 mg/dL. To determine if the condition is due to cholestasis, blood should be tested for which of the following? \nSelect and explain. \nA. Direct and indirect bilirubin, B. Alkaline phosphatase, C. Serum glutamic-oxaloacetic transaminase (SGOT), D. Serum glutamic-pyruvic transaminase (SGPT)', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Pruritus occurs frequently in untreated obstructive jaundice. Bile salt elevation is a possible cause of pruritus. Patients with generalized pruritus should have alkaline phosphatase levels determined; if levels are elevated, the possibility of cholestatic jaundice should be considered. Bilirubin is not always elevated in obstructive jaundice.', 'role': 'assistant'}]