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
Which is/are not transpo protein (s): 
Select and explain. 
A. Transferrin, B. Collagen, C. Ceruloplasmin, D. Hemoglobin
B: Collagen
Answer: B: Collagen 
Explanation: B i.e. CollagenAlbumin, ceruloplasmin, transferrinn and hemoglobin are transpo proteins whereas collagen is a structural protein.