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: Social & Preventive Medicine
The vaccines is yet to be available for 
Select and explain. 
A. Yellow fever, B. Japanese encephalitis, C. Dengue fever, D. Russian spring summer encephalitis
C: Dengue fever
Answer: C: Dengue fever 
Explanation: None