The Results of a Second Trimester Screen for Your Patient $\beta$

The results of a second trimester screen for your patient are the following: Low levels of unconjugated estriol
Low levels of maternal serum α-fetoprotein
High levels of free $\beta$ -human chorionic gonadotropin
With what fetal disorder are these results consistent?

A) Trisomy 13
B) Trisomy 18
C) Trisomy 21
D) Neural tube defect
E) Not enough information is provided