Which of the Following Phenomena Casts Doubt on the Suggestion

Multiple Choice

Which of the following phenomena casts doubt on the suggestion that undeveloped parts of the brain are solely responsible for the teenage proclivity to act in unreasonable and irrational manners?

A) fMRI readings of impulsive teenagers have been found to be identical to fMRI results in non-impulsive teenagers.
B) Twin studies have not found a high concordance of teenage acting out between monozygotic twins.
C) Impulsive behaviours do not routinely appear in adolescents in non-Westernised countries.
D) The use of medications designed to "calm down" impulsive teenagers has been generally ineffective across most research studies.