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: Dental
All causes erythema multiforme except – 
Select and explain. 
A. HSV, B. Drugs, C. Idiopathic, D. HPV
D: HPV
Answer: D: HPV 
Explanation: Idiopathic erythema multiforme is the most common cause of EM.
Herpes simplex is the most important infectious cause of EM.
Drugs, like NSAIDs & phenytoin can cause EM.