With reference to the various important provisions of the Indian constitution, consider the following pairs:
Article No — Subject Matter
1. Article 352 — Imposition of National Emergency
2. Article 356 — Duty of Union to protect States against external aggression & internal disturbance
3. Article 360 — Failure of constitutional machinery in states
4. Article 365 — Effect of failure to comply with directions given by the Union to states
How many pairs given above are correctly matched?