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
External genitalia earliest diagnosed by USG by : 
Select and explain. 
A. 10 weeks, B. 14 weeks, C. 16 weeks, D. 18 weeks
A: 10 weeks
Answer: A: 10 weeks 
Explanation: 10 weeks