Ans. (B) Parvovirus B-19Exanthema infectiosum:The characteristic rash first appears as erythematous flushing on the face in a slapped cheek appearance (red cheek).The most common manifestation of parvovirus B19 is erythema infectiosum, also known as fifth disease, which is a benign, self-limited exanthematous illness of childhood.It was the 5th in a classification scheme of common childhood exanthems.The preceding 4 exanthems were measles, scarlet fever, rubella, and Filatov-Dukes disease (an atypical scarlet fever), with roseola infantum as the "sixth disease