This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'Which one of the following is the primary site of production of gastrin \nSelect and explain. \nA. Pylorus, B. Antrum, C. Pancreas, D. Small intestine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Gastrin secreted by\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0G cells in the antral and duodenal mucosa.\n-\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0TG cells in stomach and ileum\n-\xa0 \xa0 \xa0 \xa0 Pituitary, brain and nerves\n-\xa0 \xa0 \xa0 \xa0 Pancreatic islets in the fetus', 'role': 'assistant'}]