A 24-year-old woman is in a car accident and is taken to an emergency room, where she receives a chest x-ray and a film of her lower spine. It is later discovered that she is 10 weeks pregnant. She should be counseled that
The fetus has received 50 rads Either chorionic villus sampling (CVS) or amniocentesis is advisable to check for fetal chromosomal abnormalities At 10 weeks, the fetus is paicularly susceptible to derangements of the central nervous system The fetus has received less than the assumed threshold for radiation damage