This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
All of the following statements about sodium fluoride in otosclerosis are true, except 
Select and explain. 
A. Acts by inhibiting proteolytic enzymes in cochlea, B. Acts by inhibiting osteoblastic activity, C. Is contraindicated in chronic nephritis, D. Is indicated in patients with a positive schwaze sign
B: Acts by inhibiting osteoblastic activity
Answer: B: Acts by inhibiting osteoblastic activity 
Explanation: Sodium fluoride acts by inhibiting proteolytic enzymes in the cochlea and not by inhibiting osteoblastic activity. Sodium fluoride had been tried to hasten the maturity of active focus and arrest fuher cochlear loss, but controversies exist and this treatment is not recommended generally. Ref: Diseases of EAR, NOSE and THROAT by PL Dhingra; 7th Edition, pg no. 97