Step 1: Understanding the Phrase.
The phrase "procedure established by law" is a key part of Article 21, which guarantees protection of life and personal liberty. It means that a person can be deprived of these rights only according to a lawfully enacted procedure.
Step 2: Judicial Interpretation.
Initially, Article 21 required only a valid procedure made by law. But after the Maneka Gandhi judgment (1978), the Supreme Court held that this procedure must be just, fair, and reasonable — expanding the scope of Article 21.
Step 3: Checking the Options.
(A) Article 14 deals with equality before the law.
(B) Article 19 deals with freedoms like speech and movement.
(C) Article 21 clearly contains the phrase "procedure established by law".
(D) Article 25 deals with freedom of religion.
Step 4: Conclusion.
Hence, the phrase "procedure established by law" appears in Article 21.