Which best describes the problem-solving approach of the concrete operational thinker? systematic hypothesis testing scientific trial and error they cannot devise solutions to problems?

Trial and Error best describes the problem-solving approach to the concrete operational thinker because children during 7 to 12 years old think unsystematically for a solution.

Moreover, concrete operational thinkers uses several methods to solve a problem. When one method does not work, then another method is use until it satisfy the problem. This example defines trial and error method.