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': 'Transvaginal USG can detect fetal cardiac activity in: \nSelect and explain. \nA. 6 weeks, B. 7 weeks, C. 8 weeks, D. 10 weeks', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is a i.e. 6 weeks Embryonic investigations suggest that cardiac contractions begin in fetus at 36 days gestational age.deg This is evident on : Transvaginal USG At 6 weeks of gestational age corresponding to 13 - 18mm of MSD Transabdominal USG At 8 weeks of gestational age corresponding to 25 mm of MSD. Note : MSD is mean Sac diameter According to Williams Obs 23/e p 200 Using real time sunography with a vaginal transducer fetal cardiac activity '-'?0 hs seen as early as 5th menstrual week", 'role': 'assistant'}]