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
Which of the following drugs is used for painful diabetic neuropathy 
Select and explain. 
A. Duloxetine, B. Pregabalin, C. Amitriptyline, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Answer is D (All of the above): Amitriptyline may all be used for treatment of painful diabetic neuropathy. Two agents, Duloxetine and Pregabalin have been approved by the U.S. FDA for pain associated with diabetic neuropathy -