Koplik's Spots are seen in -

Ans. is 'a' i.e., Rubeola Clinical features of measles (rubeola)o Clinical features are divided into following stages :-1) Prodromal stage# It begins 10 days after the infection and is characterized by fever, coryza with sneezing, lacrimation and photophobia. A day or two before eruptive phase (appearance of rash), Koplik spot (pathognomonic of measles) appears on buccal mucosa, opposite the 1st and 2nd lower molars.2) Eruptive phase# It begins 14 days after infection. A maculopapular rash begins behind the ears and spreads rapidly.3) Post measle stage# It is characterized by weight loss, growth retardation, diarrhea, cancrum oris, candidiasis, reactivation of TB and malnutrition particularly vitamin A deficiency (keratomalacia, xerophthalmia).