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
Earliest anomaly to be detected in ultrasound is: 
Select and explain. 
A. Anencephaly, B. Spina bifida, C. Meningocele, D. Horseshoe kidney
A: Anencephaly
Answer: A: Anencephaly 
Explanation: 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.