Jean Piaget is a central figure in developmental psychology, best known for his stage theory of cognitive development. He proposed that children progress through four distinct stages of intellectual growth—sensorimotor, preoperational, concrete operational, and formal operational—as they actively construct their understanding of the world. His work revolutionized our understanding of how children think, reason, and solve problems compared to adults.

David's statement shows he thinks there is more water after pouring, indicating he doesn't comprehend that the amount of water remains the same despite the change in container shape and size. This lack of conservation is a hallmark of the preoperational stage in Piaget's theory, where children focus on a single perceptual feature, such as height, while ignoring other relevant dimensions like width.

Piaget proposed that children adapt to their environment through two primary processes: assimilation, where new information is incorporated into existing schemas, and accommodation, where existing schemas are modified to fit new information. Together, these processes allow for cognitive growth and the development of more complex mental structures as the child matures.

Symbolic thought, babbling, and object permanence are milestones associated with infancy and early childhood (Piaget's sensorimotor and preoperational stages). In contrast, postconventional moral reasoning, as defined by Lawrence Kohlberg, represents the highest level of moral development, which typically does not emerge until late adolescence or adulthood, reflecting a shift toward abstract ethical principles.

The formal-operational stage is marked by the transition from concrete thinking to abstract reasoning. Adolescents in this stage can contemplate hypothetical scenarios, evaluate moral and social principles, and think about the future or complex societal issues. This cognitive shift allows for more sophisticated problem-solving and the ability to consider multiple perspectives on abstract concepts, moving beyond the limitations of concrete, physical experience.

Carol Gilligan challenged Kohlberg's theory, arguing that it was biased toward a male perspective of justice and autonomy. She proposed an alternative 'ethics of care' framework, suggesting that women often prioritize interpersonal relationships and the needs of others in their moral reasoning, which she felt was undervalued in Kohlberg's original model.

According to Piaget, children under the age of 7 are typically in the preoperational stage, which is characterized by symbolic thought but lacks the ability to perform logical, abstract mental operations. Abstract operations, such as conservation and logical reasoning, generally emerge during the concrete operational stage, which begins around age 7. Therefore, stating that younger children possess abstract mental operations is incorrect.

The concrete operational stage occurs roughly between ages 7 and 11. During this phase, children develop the ability to perform logical operations on concrete, physical objects. They can understand concepts like conservation, reversibility, and classification. However, their reasoning is still largely tied to physical reality and they struggle with purely abstract or hypothetical propositions until they reach the formal operational stage.

Conservation is a key concept in Piaget's theory of cognitive development, typically emerging during the concrete operational stage. It represents the child's ability to understand that quantity, length, or number of items is unrelated to the arrangement or appearance of the object. This cognitive shift allows children to move beyond superficial perceptions and grasp logical principles of invariance.

Option B is incorrect because Piaget defined the sensorimotor stage as occurring from birth to approximately two years of age. The period from two to seven years is actually classified as the preoperational stage, which is characterized by the development of symbolic thought and language, rather than the sensory-based learning of the sensorimotor stage.