This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
Karyotyping of fetus can be done by all Except 
Select and explain. 
A. Chorionic villus sampling, B. Cordocentesis, C. Amniocentesis, D. Fetal skin biopsy
D: Fetal skin biopsy
Answer: D: Fetal skin biopsy 
Explanation: Karyotyping is a test to examine chromosomes in a sample of cells. This test can help identify genetic problems as the cause of a disorder or disease. In utero sampling of fetal skin, liver, and muscle may be required to diagnose before-bih disorders that cannot be diagnosed by analysis using chorionic villi or amniotic fluid. Refer robbins 158