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: Anatomy
Most common cause of Cushing syndrome 
Select and explain. 
A. Pituitary adenoma, B. Adrenal adenoma, C. Exogenous steroids, D. Ectopic ACTH
C: Exogenous steroids
Answer: C: Exogenous steroids 
Explanation: Reference Robbins page no Pg 1125 What are the symptoms of Cushing's syndrome? weight gain. thin arms and legs. a round face. increased fat around the base of the neck. a fatty hump between the shoulders. easy bruising. wide purple stretch marks, mainly on the abdomen, breasts, hips, and under the arms. weak muscles