This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Radiology
[{'content': 'Which one of the following ultrasound marker is associated with greatest increased risk for Trisomy 21 in fetus \nSelect and explain. \nA. Echogenic foci in heart, B. Hyperechogenic bowel, C. Choroid plexus cysts, D. Nuchal edema', 'role': 'user'}, {'content': 'Answer: D \nExplanation: (D) Nuchal edemaINCIDENCE OF MAJOR & MINOR DEFECTS/MA Trisomy 21NormalLikelihood ratio for isolated marker* Nuchal Fold33.5%0.6%9.8* Short humerus33.4%1.5%4.1* Short femur41.4%5.2%1.6* Hydronephrosis17.6%2.6%1.0* Echogenic focus in heart28.2%4.4%1.1* Echogenic bowel13.3%0.6%3.0* Major defect21.4%0.65%5.2', 'role': 'assistant'}]