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: Medicine
The most common cause of Cushing&;s syndrome is: 
Select and explain. 
A. Pituitary adenoma, B. Adrenal adenoma, C. Ectopic ACTH, D. Iatrogenic steroids
D: Iatrogenic steroids
Answer: D: Iatrogenic steroids 
Explanation: The most common cause of Cushing&;s syndrome is Iatrogenic administration of steroids for a variety of reasons." REF: Harrison book of internal medicine 21ST EDITION