Final answer:
According to the study by Caldwell and Darling, spending time after school with friends is most problematic when parental supervision is lacking. Proper parental supervision is important for shaping the behavior and choices of teenagers.
Step-by-step explanation:
According to the study by Caldwell and Darling presented in the textbook, spending time after school with friends is most problematic under the circumstance when parental supervision is lacking. Adolescents are more likely to engage in risky behaviors and experience negative outcomes when they lack proper parental supervision. Parental support and guidance play a crucial role in shaping the behavior and choices of teenagers.