Letter C is the correct answer.
The Concrete Operational Stage was the third stage in the Cognitive Development Theory proposed by the very well-known psychologist and developmental biologist Jean Piaget. During the concrete operational stage, thought is rule-oriented and logical. However, it is limited to what is tangible and real. At this stage, children are mature enough to solve problems through operations, but they can only do so by applying logic to physical objects. Thus, they're usually not able to think hypothetically.