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: Medicine
All of the following are used for treatment of stiff person syndrome, EXCEPT: 
Select and explain. 
A. Diazepam, B. Valproate, C. IV Ig, D. None of the above
D: None of the above
Answer: D: None of the above 
Explanation: Optimal treatment of stiff-person syndrome requires therapy of the underlying tumor, glucocoicoids, and symptomatic use of drugs that enhance GABA-ergic transmission (diazepam, baclofen, sodium valproate, tiagabine, vigabatrin). A benefit of IVIg has been demonstrated for the nonparaneoplastic disorder but remains to be established for the paraneoplastic syndrome. Ref: Harrison's principle of internal medicine 17th edition, chapter 97