This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
Which of the following drug is not used for overactive bladder? 
Select and explain. 
A. Duloxetine, B. Darifenacin, C. Oxybutynin, D. Flavoxate
A: Duloxetine
Answer: A: Duloxetine 
Explanation: .