Which act expanded services to preschool children aged 3-5?

The choice that addresses the expansion of services to preschool children aged 3-5 is the legislation established under PL 99-457. This law amended the Individuals with Disabilities Education Act (IDEA) and specifically provided funding and guidelines for states to offer special education and related services to children in this age group. This legislative act recognized the importance of early intervention and the need for educational supports for younger children with disabilities.

The significance of PL 99-457 lies in its focus on early childhood education, which laid the groundwork for inclusive practices and access to services for preschool children with disabilities, ensuring they received the support they need at a crucial stage of development. This act was key in promoting the development of a continuum of services for young children, which is vital for helping them reach their full potential.

In contrast, the other choices are related but do not specifically expand services to the preschool age group in the same direct manner.