The correct option is Article 21.
Explanation
Part III of the Constitution of India (Articles 12-35) enshrines Fundamental Rights. The "Right to Freedom" is a cluster of rights covered under Articles 19 to 22, which are essential for the functioning of a democratic society.
Option Analysis:
- Article 21 is Correct: Article 21 states that "No person shall be deprived of his life or personal liberty except according to procedure established by law." It is available to both citizens and non-citizens.
- Article 19 is Incorrect: Article 19 guarantees six democratic freedoms: freedom of speech and expression, assembly, association, movement, residence, and profession.
- Article 22 is Incorrect: Article 22 deals with protection against arrest and detention in certain cases, providing procedural safeguards to detained persons.
- Article 20 is Incorrect: Article 20 provides protection in respect of conviction for offences, covering immunity from ex-post-facto laws, double jeopardy, and self-incrimination.
Key Takeaway:
Article 21 is the specific constitutional provision that guarantees the fundamental right to life and personal liberty.