This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Physiology
Commonest cause for hyperparathyroidism is 
Select and explain. 
A. Single adenoma, B. Multiple adenomas, C. Single gland hyperplasia, D. Multiple gland Hyperplasia
A: Single adenoma
Answer: A: Single adenoma 
Explanation: A parathyroid adenoma causes the affected gland to release more PTH than it should. This disrupts your calcium and phosphorus balance. This condition is called hyperparathyroidism. Ref ganong's review of medical physiology 25e