You are answering a USMLE-style medical question. Question: A 34-year-old woman comes to the physician requesting prenatal care. For the past 2 months, she has had increasing breast tenderness, nausea, 3-kg (6.6-lb) weight gain, and urinary frequency. She is not sure about the date of her last menstrual period. She has been trying to conceive with her husband since she stopped taking oral contraceptives 6 months ago; she was happy to tell him last week that she is pregnant. Her temperature is 37.2°C (99°F), pulse is 100/min, and blood pressure is 110/60 mm Hg. Physical examination shows mild, nontender abdominal enlargement. The cervical os is closed. Urine β-hCG is negative. Transvaginal ultrasonography shows no abnormalities. Which of the following is the most likely diagnosis? Options: A) Delusion of pregnancy B) Pseudocyesis C) Pregnancy D) Incomplete abortion Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.