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 of Cushing syndrome is 
Select and explain. 
A. Adrenal adenoma, B. Carcinoma, C. Atrophy, D. Hyperplasia
D: Hyperplasia
Answer: D: Hyperplasia 
Explanation: MC cause of Cushing's syndrome is iatrogenic exogenous administration of steroids. MC endogenous cause of Cushing's syndrome is bilateral adrenal hyperplasia secondary to hypersecretion of ACTH from pituitary or from an ectopic non-pituitary source