Answer:
Formal stage
Explanation:
The formal stage is the last or the fourth stage in the cognitive development stage of Jean Piaget. The formal stage is about the person think rationally and abstractly. This stage develops the ego-centrism and reason argue and the plan. This stage starts from 12 to adulthood. At this stage, the person starts to think critically. This stage considers the problem.
The fourteen-year-old Jennifer was at the stage of formal in cognitive development.
