Which of the Following Would NOT Be Considered a Red

Which of the following would NOT be considered a red flag in speech and language development?

A) The child does not respond to "no" or changes in tone of voice between 0-3 months.
B) The child does not answer simple "who," "what," and "where" questions or be understood by people outside the family between 1 and 2 years of age.
C) The child cannot understand differences in meaning or string together two or three words between 2-3 years.
D) The child has not developed correct syntax and pronoun usage by 2 years of age.