Quincy's grandmother takes him to the store to choose a gift for his younger sister's first birthday party. Quincy chooses an action figure of his favorite superhero, Spiderman. Quincy is confused when his grandmother says, "I don't think your little sister will like Spiderman. Let's find something else she'll know how to play with better!" What concept of cognitive development is Quincy demonstrating?

a.

conservation

b.

object permanence

c.

theory-of-mind

d.

egocentrism