Which one of the following Articles of Indian Constitution provides that “it shall be the duty of the Union to protect every State against external aggression and internal disturbance”?

Q. Which one of the following Articles of Indian Constitution provides that “it shall be the duty of the Union to protect every State against external aggression and internal disturbance”?

1. Article 215
2. Article 275
3. Article 325
4. Article 355

Answer: Article 355