<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 25-year-old G1P0000 presents to her obstetricians office for her first prenatal visit. She had a positive pregnancy test 6 weeks ago, and her last period was about two months ago, though at baseline her periods are irregular. Aside from some slight nausea in the mornings, she feels well. Which of the following measurements would provide the most accurate dating of this patients pregnancy?? A: Biparietal diameter, B: Femur length, C: Abdominal circumference, D: Serum beta-hCG, E: Crown-rump length,  <response>: This is a question about estimating gestational age in a pregnant patient. The key information is that this is the patients first prenatal visit, she is 6 weeks from her last menstrual period, and her periods are irregular at baseline. To date a pregnancy accurately, we need a measurement that reflects fetal size and growth. Biparietal diameter, femur length, abdominal circumference, and crown-rump length all reflect fetal size. Serum beta-hCG reflects placental function rather than fetal size.Of the fetal size measurements, crown-rump length is most accurate in early pregnancy. The other measurements become more useful later in pregnancy as the fetus grows.E: Crown-rump length 