1. 'Due Process of Law' is a legal doctrine that requires fairness in legal proceedings and in the laws themselves. It ensures that the government cannot deprive individuals of life, liberty, or property without appropriate legal procedures and safeguards.
2. Option (A) The principle of natural justice is a core component of due process. It includes the right to a fair hearing (audi alteram partem) and the rule against bias (nemo judex in causa sua). These principles ensure procedural fairness, which is central to the meaning of due process.
3. Option (B) The procedure established by law (as originally interpreted under Article 21 of the Indian Constitution) primarily focuses on whether the prescribed legal procedure has been followed, without necessarily questioning the fairness or reasonableness of the law itself. Due process is broader, encompassing substantive fairness as well.
4. Option (C) Fair application of law relates to procedural due process but doesn't fully capture the substantive aspect (fairness of the law itself).
5. Option (D) Equality before law (Article 14) is a related but distinct fundamental right ensuring non-discrimination.
6. In essence, Due Process emphasizes fairness, reasonableness, and justice in both procedure and substance, which is best captured by the underlying principles of natural justice.