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
[{'content': 'USG can detect gestation sac earliest at – \nSelect and explain. \nA. 5–6 weeks of gestation, B. 7–8 weeks of gestation, C. 10 weeks of gestation, D. 12 weeks of gestation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The gestational sac can be visualized as early as 41/2 weeks by transvaginal USG and 5 weeks by transabdominal USG.', 'role': 'assistant'}]