Concept:
The Indian legal aid system is structured to be "vertically integrated." This means that the protection of law and the assistance of counsel must be available at every level of the judiciary to ensure a fair trial and the right to appeal.
Step 1: The Tiered Structure of Legal Services.
The Legal Services Authorities Act, 1987, established a hierarchy of bodies to provide aid:
$\text{NALSA (National level)} \rightarrow \text{Supreme Court}$
$\text{SLSA (State level)} \rightarrow \text{High Courts}$
$\text{DLSA (District level)} \rightarrow \text{District/Subordinate Courts}$
$\text{TLSC (Taluk level)} \rightarrow \text{Munsif/Magistrate Courts}$
Step 2: Universality of Coverage.
Legal aid is not "confined" to any single tier. If a poor person is involved in a small dispute in a village court, they are entitled to aid. If that same person’s case eventually reaches the Supreme Court through the process of appeal, the state is still obligated to provide them with a lawyer if they cannot afford one.
Step 3: Conclusion.
Therefore, the scope of free legal aid extends from the "lowest Court to the Supreme Court of India." Options A, B, and C are incorrect because they use the restrictive word "confined," which contradicts the inclusive nature of Indian social justice.
Final Answer: Option D