This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
Most common cause of hypehyroidism- 
Select and explain. 
A. Thyroid hyperplasia, B. Thyroid adenoma, C. Thyroid carcinoma, D. Grave disease
D: Grave disease
Answer: D: Grave disease 
Explanation: Most common cause of hypehyroidism is Graves' disease - 76% followed by Toxic Multinodular goitre - 14% and Toxic Solitary thyroid adenoma - 5%. Reference : page 740 Davidson's Principles and practice of Medicine 22nd edition