The Eklavya Model Residential Schools aim to provide quality education to tribal students. This means that option 2 is the correct choice.

Option 1, Scheduled Caste students, is not the objective of these schools. While both tribal and Scheduled Caste students face educational challenges and inequalities, the Eklavya Model Residential Schools specifically focus on improving the educational opportunities for tribal students.

Option 3, orphan girl students, is also not the objective of these schools. While providing education and support to orphan girls is a noble cause, the Eklavya Model Residential Schools have a specific focus on tribal students.

Option 4, unorganized women labour, is unrelated to the objective of these schools. The Eklavya Model Residential Schools are not aimed at providing education to unorganized women laborers. They are specifically designed to address the educational needs and challenges faced by tribal students.

In conclusion, the correct answer to the question is option 2, tribal students. The Eklavya Model Residential Schools aim to provide quality education to these students.