This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
A 40-year-old woman with hypertension comes to the physician because of excessive thirst, excessive urination, constipation, and a depressed mood. Her medications include hydrochlorothiazide. Laboratory studies show a serum calcium level of 11.0 mg/dL. 
Which of the following underlying disorders is most likely? 
Select and explain. 
A. Medullary carcinoma of the thyroid, B. Multiple myeloma, C. Parathyroid adenoma, D. Porphyria
C: Parathyroid adenoma
Answer: C: Parathyroid adenoma 
Explanation: None