Two-year-old alma has many new toys in her playpen. nonetheless, even before playing with these toys, she wants to explore the room and tries to escape the playpen. alma is motivated to escape the playpen:

What was piaget's explanation as to why preschool-age children in the preoperational stage make errors on tasks requiring conservation? a) preschool children's tendency toward centration prevents them from focusing on other relevant features of a situation b) preschool children have not yet developed numerical understanding; therefore, different amounts are meaningless c) preschool children's neural-visual network is not fully matured d) preschool children have not lived long enough and accrued enough experience to know the difference between quantities