The correct answer is B. Adults must follow the advice they give children.
Step-by-step explanation:
In the excerpt presented the narrator explains during kindergarten adults teach children to behave, this includes "to not fight with others", "not to hurt other creatures" and "to respect others"; these behaviors are contrasted with some behaviors shown by adults the narrator previously explained that included spending money in war. This contrast suggests the behaviors adults teach children which are positive behaviors are not those adults display, due to this, the narrator or author implicitly suggest adults should follow the behavior they teach in kindergarten or "Adults must follow the advice they give children".