Helen gets upset that she only has one cookie while her older brother has two. Helen's mom breaks her cookie in half but Helen complains, "That's still not the same. He still has more than me!" Which of the following is true? a. Helen lacks conservation which is why she is upset. b. Helen has egocentrism and can't understand why the situation is fair. c. Helen's lack of object permanence explains her behavior. d. Helen has conservation which is why she is upset.