A nurse is using Jean Piaget's developmental theory to focus on cognitive development. Which area will the nurse assess in this patient?

A. This refers to Kohlberg’s theory of moral development, not Piaget. B. This refers to Erikson’s psychosocial stages, specifically young adulthood. C. This refers to a stage in Freud’s psychosexual development, not Piaget's. D. Formal operations is the last stage in Piaget's theory (ages 11+), focusing on abstract reasoning, logical thinking, and problem-solving.