Which example would most strongly argue against the sequence of stages in Piaget's theory of cognitive development?

• A. A study finds that language acquisition does not strictly follow Piaget's stages.
• B. Research shows that some children can perform operations in the formal operational stage at a much younger age.
• C. Observations indicate that not all adults reach the formal operational stage.
• D. Evidence that children's learning is enhanced through social interaction.

Answer: (B)