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: Gynaecology & Obstetrics
[{'content': 'Cause of oligohydramnios is: \nSelect and explain. \nA. Oesophageal atresia, B. Duodenal atresia, C. Rena! agenesis, D. Diabetes', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Rena! agenesis', 'role': 'assistant'}]