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
The most common cause of sporadic viral encephalitis is - 
Select and explain. 
A. Japanese B encephalitis, B. Herpes simplex encephalitis, C. Human immunodeficiency virus encephalitis, D. Rubeola encephalitis
B: Herpes simplex encephalitis
Answer: B: Herpes simplex encephalitis 
Explanation: None