This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: ULTRASOUND, Subject name: Radiology
[{'content': 'Earliest anomaly to be detected in ultrasound is: \nSelect and explain. \nA. Anencephaly, B. Spina bifida, C. Meningocele, D. Horseshoe kidney', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Earliest anomaly to be detected in ultrasound is Anencephaly (as early by 10th week) Anencephaly in Ultrasound: Acrania Loosely arranged brain parenchyma Frog Eye Appearance Figure: Frog eye sign and irregularly outlined brain patter protruding freely into amniotic fluid is seen, with absence of cranial vault.', 'role': 'assistant'}]