In Piaget's formal operational developmental stage, what is the main characteristic?

Choice A reason: Self-absorption is more characteristic of adolescent egocentrism, such as the imaginary audience or personal fable, but it is not the defining cognitive feature of the formal operational stage. Choice B reason: Circular reactions are part of Piaget’s sensorimotor stage, where infants repeat actions to explore their environment. This is not relevant to formal operational thinking. Choice C reason: Hypothetico-deductive thinking is the hallmark of the formal operational stage. It involves the ability to think abstractly, formulate hypotheses, and systematically test them. This stage typically begins around age 11 and enables scientific reasoning and complex problem-solving. Choice D reason: Syllogistic reasoning is a component of logical thinking but is not the defining feature of the formal operational stage. It may emerge earlier and does not encompass the full scope of abstract reasoning seen in this stage.