You are answering a USMLE-style medical question. Question: A 55-year-old woman presents to the office because she has been feeling weak. For the past 2 years, she has been urinating a considerable volume every time she goes to the bathroom. She has no past medical history. Her heart rate is 86/min, respiratory rate is 15/min, temperature is 37.4°C (99.3°F), and blood pressure is 111/79 mm Hg. Laboratory studies are significant for the following: Calcium 13.8 mg/dL PTH 230 pg/mL Her complete metabolic panel is otherwise within normal limits. Imaging studies show subperiosteal resorption and osteoporosis. Scintigraphy reveals the most common pathologic condition associated with the patient’s diagnosis. Which of the following is the most likely diagnosis in this patient? Options: A) Adenoma B) Carcinoma C) Decreased calcitriol concentration D) Phosphate retention Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.