<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 24-year-old woman with a missed menstrual cycle has a positive pregnancy test. The estimated gestational age is 4 weeks. The patient questions the pregnancy test results and mentions that a urinary pregnancy test she took 3 weeks ago was negative. What is the explanation for the patients first negative pregnancy test result?? A: The embryonic liver has not yet developed to produce human chorionic gonadotropin at that term., B: The syncytiotrophoblast had not yet developed to produce human chorionic gonadotropin at that term., C: Pregnancy test becomes positive during organogenesis so should be expected positive no earlier than at week 4., D: Human chorionic gonadotropin starts to be produced by the uterus only after the embryonic implantation which has not yet occurred., E: Human chorionic gonadotropin can only be found in the urine after its placental production is started.,  <response>: This is a question about the timing of when human chorionic gonadotropin hCG becomes detectable in urine during early pregnancy. The key pieces of information are:- The patient had a negative pregnancy test 3 weeks ago but now has a positive test at estimated 4 weeks gestation- We need to explain why the first test was negative- The choices mention hCG production from different sources embryonic liver, syncytiotrophoblast, uterus at different gestational timepointsB: The syncytiotrophoblast had not yet developed to produce human chorionic gonadotropin at that term. 