You are answering a USMLE-style medical question. Question: A 42-year-old woman presents to her obstetrician for a prenatal care appointment at 10 weeks gestation. The patient recently found out she was pregnant after having unprotected intercourse with her husband for the past year. She states that she is feeling well and has experienced some nausea and vomiting. She is currently taking prenatal vitamins and folate supplements. Her temperature is 99.5°F (37.5°C), blood pressure is 127/68 mmHg, pulse is 90/min, respirations are 19/min, and oxygen saturation is 98% on room air. On physical exam, you notice a gravid uterus 10 cm above the pubic symphysis. The patient's external genitalia appear within normal limits. Which of the following is the next best step in management? Options: A) Amniocentesis B) Cell-free DNA testing C) Chorionic villus sampling D) Regular follow up appointments Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.