This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nose and paranasal sinuses, Subject name: ENT
CSF rhinorrhoea is diagnosed by - 
Select and explain. 
A. Beta 2 microglobulin, B. Beta 2 transferrin, C. Thyroglobulin, D. Transthyretin
B: Beta 2 transferrin
Answer: B: Beta 2 transferrin 
Explanation: Beta 2 transferring is a protein seen in CSF and not in nasal discharge. Thus its presence is specific and sensitive for diagnosing CSF rhinorrhea. (Ref: Textbook of diseases of ENT, PL Dhingra, 7th edition, pg no. 184)