Sandra has begun to test her reasoning against her experience; she uses accommodation to adjust to the many cognitive changes that she encounters. Sandra is in the stage of

Sandra is in the stage of "late formal operational thought".

The formal operational stage is the fourth and last phase of Jean Piaget's hypothesis of cognitive development. Now being developed, thinking turns out to be substantially more modern and progressed. Children can consider dynamic and hypothetical ideas and utilize rationale to concoct inventive answers for issues.