Answer:
formal operations
Step-by-step explanation:
In the period of formal operations the young man is already able to reason about hypotheses insofar as he is able to form abstract conceptual schemes and through them to perform mental operations within the principles of formal logic. With this, the adolescent acquires "the capacity to criticize social systems and propose new codes of conduct: discusses moral values of their parents and builds their own (thus acquiring autonomy)".
An example of the period of formal operations can be seen in the question above, where a teenager was able to think for himself how to test the hypotheses of an experiment to arrive at a concrete conclusion about it.