This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
Which of the following is the "Least Common Chronic" complication of measles? 
Select and explain. 
A. Diarrhoea, B. Pneumonia, C. Otitis media, D. SSPE
D: SSPE
Answer: D: SSPE 
Explanation: Ans. is 'd' i.e., SSPE(Ref: PSM Park, 19th/e, p. 128)* Subacute sclerosing panencephalitis (SSPE) is a rare complication (1 in 300000) of measles, which develops many years after the initial infection.* SSPE belongs to group C slow virus infection, caused by a defective Measles virus.