Which of the Following Statements Is NOT True, According to Your

Which of the following statements is NOT true, according to your text?

A) Many clinicians believe that any substance use during childhood and adolescence is a sign of a serious problem.
B) Clinicians are able to rely on clear definitions of "childhood" and "adulthood."
C) Some clinicians believe that experimental drug use is a regular aspect of adolescence.
D) Adolescence in industrialized countries seems to have been extended.