Detailed Explanation:

Correct Answer: Option 3 (Inter-State quarantine is a Union subject under the Union List)

The Seventh Schedule of the Constitution divides subjects between the Union and States through the Union List, State List, and Concurrent List. Matters having national importance or requiring uniform regulation across states are generally placed in the Union List.

❌ Option 1 is Incorrect: Inter-State trade and commerce is a Union List subject, not a State List subject.

❌ Option 2 is Incorrect: Inter-State migration and inter-State movement fall under the Union List, not the State List.

✅ Option 3 is Correct: Inter-State quarantine is included in the Union List (Entry 81) because disease control across state boundaries requires central coordination.

❌ Option 4 is Incorrect: Corporation tax is levied by the Union Government and is a Union List subject.

Short Notes: Seventh Schedule of the Constitution

• The Seventh Schedule distributes legislative powers between the Union and States.

• It contains Union List, State List, and Concurrent List.

• The Union List currently has around 100 subjects of national importance.

• The State List contains subjects of local and regional importance.

• The Concurrent List allows both Parliament and State Legislatures to make laws.

• In case of conflict on a Concurrent List subject, Union law prevails.

• Inter-State trade, migration, quarantine, citizenship, defence, and corporation tax are Union List subjects.

• The scheme of distribution is based on Articles 246 and 246A.