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
[{'content': 'Fetal cardiac activity is detected with Transvaginal USG as early as? \nSelect and explain. \nA. 6 weeks, B. 8 weeks, C. 10 weeks., D. 12 weeks', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 6weeks REF: USG in Obstetrics & Gynecology by Callen 4th edition page 119-120 Fetal cardiac activity is detected as early as With Transvaginal USG 6 weeks of gestational age With Transabdominal USG', 'role': 'assistant'}]