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: Radiology
[{'content': 'Assymetric growth on ultrasound imaging is seen in \nSelect and explain. \nA. Anencephaly, B. Trisomy 18, C. Congenital rubella syndrome, D. Renal anomalies', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Anencephaly', 'role': 'assistant'}]