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': "Which of the following is false regarding cell free DNA \nSelect and explain. \nA. Detected in maternal blood, B. Prenatal diagnosis of Down's syndrome can be made, C. Used for liquid biopsy, D. It is one of the invasive techniques for  prenatal diagnosis of certain genetic diseases", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Prenatal diagnosis can be made by invasive and non invasive techniques.\nInvasive techniques include aminocentesis, chorionic villous sampling, cord blood sampling. Cell free DNA is a non invasive method.', 'role': 'assistant'}]