<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 38-year-old G1P0 woman presents to her obstetrician for a prenatal visit. She reports feeling well and has no acute concerns. She is currently at 28 weeks gestation previously confirmed by ultrasound. She takes her folate supplements daily. On physical exam, the uterus is soft and globular. The top of the uterine fundus is found around the level of the umbilicus. A fetal ultrasound demonstrates a reduced liver volume and subcutaneous fat with relative sparing of the head. Which of the following is most likely the cause of this patients ultrasound findings?? A: Aneuploidy, B: Cigarette smoking, C: Fetal congenital heart disease, D: Fetal infection, E: Neural tube defect,  <response>: This is a question about interpreting fetal ultrasound findings in a pregnant patient. The key findings on ultrasound are reduced liver volume and subcutaneous fat with relative sparing of the head. This pattern is classic for intrauterine growth restriction IUGR. The most common cause of IUGR is placental insufficiency, which reduces oxygen and nutrient delivery to the fetus. This typically causes asymmetric growth restriction where the head is spared due to redistribution of blood flow to protect the brain at the expense of the trunk and extremities. Therefore, the ultrasound findings are most consistent with placental insufficiency leading to IUGR.B: Cigarette smoking 