This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fetal Imaging, Subject name: Gynaecology & Obstetrics
[{'content': 'Fetal cardiac activity is detected with Trans vaginal 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: ANSWER: (A) 6weeksREF: USG in Obstetrics & Gynecology by Callen 4ch edition page 119-120Fetal cardiac activity is detected as early asWith Transvaginal USG6 weeks of gestational ageWith Transabdominal USG8 weeks of gestational age', 'role': 'assistant'}]