A psychologist might evaluate a child's ability to answer abstract and hypothetical questions to determine whether the child is in the __________ or the __________ stage of cognitive development.

A) concrete-operations...formal-operations
B) formal-operations...sensorimotor
C) concrete-operations...postoperational
D) sensorimotor...preoperational

The ability to think abstractly and handle hypothetical situations is a hallmark of formal operational thinking. Concrete operational thinking, on the other hand, is characterized by the ability to think logically about concrete objects and events, but not yet able to handle abstract concepts. The preoperational and sensorimotor stages precede the concrete operational stage, and involve more basic cognitive abilities such as object permanence and symbolic representation. Finally, there is no "postoperational" stage recognized in Piaget's theory of cognitive development.