The correct option is State List.
Explanation
The legislative powers in India are distributed between the Union and the States under Article 246, read with the Seventh Schedule of the Constitution. This schedule classifies subjects into the Union List (List I), State List (List II), and Concurrent List (List III).
Detailed Analysis:
- Constitutional Provision: "Prisons, reformatories, Borstal institutions and other institutions of a like nature, and persons detained therein" are explicitly listed under Entry 4 of List II (State List).
- Legislative Competence: Since the subject falls under the State List, the State Legislatures have the exclusive power to make laws regarding the management and administration of prisons.
- Role of the Centre: While the primary responsibility lies with the State Governments, the Ministry of Home Affairs (Union Government) provides advice, guidance, and financial assistance for prison modernization and the implementation of best practices.
Key Takeaway: "Prisons" is a subject under the State List (List II, Entry 4) of the Seventh Schedule, giving States exclusive legislative and administrative authority over them.