IDEA 2004 mandates that students must be assessed using what kind of evaluations?

The correct choice highlights the requirement under IDEA 2004 that mandates students must be assessed using nondiscriminatory assessments. This means that when evaluating students for special education services, assessments must be fair and equitable, taking into consideration the cultural and linguistic backgrounds of the students. This ensures that the evaluation process does not lead to biased results that could misrepresent a student's capabilities or needs based on language proficiency or cultural differences.

Nondiscriminatory assessments are essential because they help provide a true and accurate picture of a student's abilities and needs. They contribute to the identification of disabilities without the influence of factors unrelated to the student’s educational potential. This principle is critical for creating individualized education plans (IEPs) that are responsive to the unique strengths and requirements of each student.

The other types of assessments mentioned do not align with these principles, as standardized assessments may not account for cultural differences, subjective assessments may vary greatly in interpretation, and assessments determined solely by school principals might lack the thoroughness and fairness necessary for proper evaluation. Thus, the focus on nondiscriminatory assessments aligns with the intent of IDEA 2004 to ensure equitable access to education for all students.