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
Gestation sac is picked up by USG earliest at 
Select and explain. 
A. 5 - 6 weeks of gestation, B. 6 - 8 weeks of gestation, C. 8 - 10 weeks of gestation, D. 12 weeks of gestation
A: 5 - 6 weeks of gestation
Answer: A: 5 - 6 weeks of gestation 
Explanation: Earliest by 4 1/2 weeks of gestation.