A nurse in a provider's office is caring for a client who is at 36 weeks of gestation and scheduled for an amniocentesis. The client asks why she is having an ultrasound prior to the procedure. Which of the following is an appropriate response by the nurse?

D This is useful for estimating fetal age. C This assists in identifying the location of the placenta and fetus. B This will determine if there is more than one fetus. A This is a screening tool for spina bifida.