The correct answer is option 3, Article-6. Article-6 of the Indian Constitution deals with the citizenship of people who migrated from Pakistan to India. It states that any person who has migrated from Pakistan to India before the 19th of July 1948 shall be considered as a citizen of India. Additionally, any person who has migrated from Pakistan to India after the 19th of July 1948 can become an Indian citizen if they fulfill certain conditions mentioned in the article. This includes having resided in India for at least six months and declaring their intention to settle in India. Therefore, Article-6 of the Indian Constitution specifically mentions the citizenship rights of people who migrated from Pakistan to India.