Koplik spots are pathognomic of -

Ans. is 'a' i.e., Measles Koplik spotso Koplik spots, the pathognomonic enanthem of measles, begin as small, bright red macules that have a 1-2-mm blue- white speck within them. They are typically seen on the buccal mucosa near the second molars in 1-2 days before and lasting 2 days after the onset of the rash.