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: Surgery
A known patient with renal stone disease developed pathological fractures along with abdominal pain and ceain psychiatric symptoms. He should be investigated for ? 
Select and explain. 
A. Polycystic kidney, B. Renal tubular acidosis, C. Hyperparathyroidism, D. Paget's disease of bone
C: Hyperparathyroidism
Answer: C: Hyperparathyroidism 
Explanation: Ans. is 'c' i.e., Hyperparathyroidism