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

1. The question asks to identify the Article of the Indian Constitution that mandates the Union to protect states against external aggression and internal disturbance. 2. Article 355 of the Indian Constitution explicitly states this duty. 3. Option (A) Article 215 relates to High Courts being courts of record. 4. Option (B) Article 275 relates to grants from the Union to certain States. 5. Option (C) Article 325 relates to no person being ineligible for inclusion in, or to claim to be included in a special, electoral roll on grounds of religion, race, caste or sex. 6. Therefore, Article 355 is the correct answer.