This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of carbohydrate, Subject name: Biochemistry
Chitin contains 
Select and explain. 
A. Alpha 1-4 bond, B. b-1-6 bond, C. Alfa 1-6 bond, D. b-1-4 bond
D: b-1-4 bond
Answer: D: b-1-4 bond 
Explanation: It is present in exoskeletons of crustacea and insects. It is composed of units of N-acetyl-glucosamine with beta -1,4-glycosidic linkage.Ref: DM Vasudevan, page no: 79