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
Anencephaly is best diagnosed at 12 weeks by : 
Select and explain. 
A. Serum alpha fetoprotein, B. Ultrasonogram, C. Radiography, D. Amniography
B: Ultrasonogram
Answer: B: Ultrasonogram 
Explanation: Ultrasonogram