Each of the Following Statements About Classification of Language Disorders

Each of the following statements about classification of language disorders is true EXCEPT

A) A primary language disorder has no known cause.
B) About half the children whose language development is delayed at age 2 will gradually catch up developmentally.
C) More than half of the children who show language impairments in kindergarten will have obvious reading problems by second grade.
D) Difficulty in using language in social interactions and relationships is an exclusive feature of secondary language disorders.