The correct answer is chorionic villus sampling.
Chorionic villus sampling is a kind of prenatal diagnosis to find the genetic or chromosomal disorders in the fetus. The transcervical method is done by administering a thin plastic tube via the cervix and vagina to reach the placenta. A small sample of chorionic villus tissue is then withdrawn.
The chorionic villi are the projections of placental tissue, which share the genetic makeup of the baby. The chorionic villus sampling is generally done between the weeks 10 and 13 of pregnancy.