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: Biochemistry
[{'content': 'Best sample for DNA karyotyping ? \nSelect and explain. \nA. Blood, B. Bone marrow, C. Amniotic fluid, D. Chorionic villi', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., BloodKaryotyping is the study of number and appearance of chromosomes,Most commonly used sample is blood. Blood is centrifuged. WBCs are separated. White Blood cells are rapidly dividing cells with DNA.", 'role': 'assistant'}]