Jean Piaget made a systematic study of cognitive development among children of different age groups and he categorized it into different developmental stages. These stages are-Sensory-motor stage (0 to 2 years)pre-operational stage (2 to 6 years)Concrete operational stage (6 to 11 years)Formal Operational stage (11+ years to adolescence).?Hypothetical deductive reasoning: Hypothetical deductive reasoning is the ability to think scientifically through generating predictions, or hypotheses, about the world to answer questions.Piaget stated that œhypothetical-deductive reasoning becomes important during the formal operational stage. This type of thinking involves hypothetical œwhat-if situations that are not always rooted in reality, i.e. counterfactual thinking.It is often required in science and mathematics.??So option (4) is the correct answer.Important PointsStagesChan?gesSensory-motor stage Senses are teachersReflex actionsIntimate Behaviorpre-operational stage Language developmentIrreversibilityEgocentrismAnimismConcrete operational stageLogic beginsReversibilityClassificationConservationFormal Operational stageHypothetical-deductive thinkingDivergent/Convergent thinking.Creative Thinking.Additional Information According to Jean Piaget, Development in a child is only based on two factors, which are-?Physical Environment.Biological abilities.?But in reference to Language development, he only recognizes cognition, According to him language is developed in a child only by his cognition, there is no interference from the environmental factor during language development.