Freedom of speech and expression is ensured under:

The correct answer is 19. The right to freedom of speech and expression is guaranteed under Article 19 of the Constitution of India. This fundamental right allows citizens to express their views and opinions freely, subject to reasonable restrictions for the sovereignty and integrity of the country, security, public order, etc.

• Article 20: Protection from conviction for offenses.
• Article 21: Protection of life and personal liberty.
• Article 22: Protection against arrest and detention.

Therefore, the correct article number is 19.