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: Biochemistry
Steroids with 8-10 c-atorm side chains at C-17 and an OH group at C3 are 
Select and explain. 
A. Androgens, B. Andrenal coicoids, C. Progestins, D. Sterols
D: Sterols
Answer: D: Sterols 
Explanation: Sterols are naturally occurring alcohols which consist basically of the steroid skeleton and which vary in the number of cyclic double bonds. To the ring system is attached an alkyl side-chain which also may have double bonds.Sterols are a subgroup of steroids with a hydroxyl group at the 3-position of the A-ring.Ref: Harpers Illustrated Biochemistry, 29th edition