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
Which of the following is false regarding cell free DNA 
Select and explain. 
A. 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
D: It is one of the invasive techniques for  prenatal diagnosis of certain genetic diseases
Answer: D: It is one of the invasive techniques for  prenatal diagnosis of certain genetic diseases 
Explanation: Prenatal diagnosis can be made by invasive and non invasive techniques.
Invasive techniques include aminocentesis, chorionic villous sampling, cord blood sampling. Cell free DNA is a non invasive method.