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: Pathology
Which of the following drugs is not effective in case of Trigeminat Neuralgia? 
Select and explain. 
A. Carbamazipine, B. acetaminophen, C. Phenytoin sodium, D. Baclofen
B: acetaminophen
Answer: B: acetaminophen 
Explanation: None