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
DOC in adrenal insufficiency? 
Select and explain. 
A. Hydrocoisone, B. Adrenaline 2012-13, C. Dexamethasone, D. Fludrocoisone
A: Hydrocoisone
Answer: A: Hydrocoisone 
Explanation: hydrocoisone is the mainstay of treatment. Dose of about 20_ 30 mg /d ( Harrison 17 pg 2264)