<prompt> A patient with clustered, white lesions on the buccal mucosa opposite the upper 1st 2nd molars pathognomonic for measles. These are:-LeukoplakiaKoplik spotsKaposi spotsNone  <response>: Koplik spots - These are white lesions on buccal mucosa opposite the first and second lower molars. They are small, bluish-white spots on a red base, smaller than the head of a pin It is pathognomonic of measles. Measles- Causative organism - RNA paramyxovirus Incubation period - 10-14 days Pathognomic cf - Koplik spots Clinical feature- retroauricular origin of rash Mc complication- serous otitis media 