Data on the Occurrence of Stuttering Across the Lifespan Indicate

Data on the occurrence of stuttering across the lifespan indicate that:

A) whereas the incidence of stuttering increases with age, its prevalence remains constant
B) the incidence of the disorder is about 1% while its prevalence is about 5% or higher
C) the prevalence of the disorder is about 1% while its incidence is about 5% or higher
D) the prevalence and the incidence are basically equal