What age group includes students who are 6 to 12 years old?

The correct choice includes students who are 6 to 12 years old because it corresponds with the typical age range for elementary education in the United States. This includes children in grades that generally fall between Prekindergarten and fifth grade, where students are usually aged 5 to 11 or 12, depending on their birth dates and school district policies.

The other age groups listed do not match this range. For instance, sixth to twelfth grade includes students who are older, typically ranging from around 11 or 12 years old up to 18. Early childhood refers to the period before age 6, focusing on preschool-aged children. Young adults are typically considered individuals aged 18 and older, usually in the context of higher education or early career stages. Thus, the age group specified in the question aligns perfectly with the educational stages spanning from Prekindergarten to fifth grade.