This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
An example of scleroprotein is 
Select and explain. 
A. Zein, B. Keratin, C. Glutenin, D. Ovoglobulin
B: Keratin
Answer: B: Keratin 
Explanation: Scleroproteins: They are insoluble in water, salt solutions and organic solvents and soluble only in hot strong acids. They form supporting tissues, e.g. collagen of bone, cartilage and tendon; keratin of hair, horn, nail and hoof. Keratin is one of the examples.
Reference: Vasudevan 7th  ed, pg 43