When Sally is asked why she should share her toys with her sister, she responds by saying "Because my

When Sally is asked why she should share her toys with her sister, she responds by saying "Because my mom says I have to and if I don't I'll go to time-out." In which stage of moral development is Sally?
Conventional Morality
Nonconventional Morality
Postconventional Morality
Preconventional Morality