Step 1: Understand the principle.
The quote says that the rules of natural justice are not limited to only quasi-judicial functions. In simple words, fairness rules must also apply to ordinary administrative actions, not just to court-like decisions.
Step 2: Recall the old position.
Before this case, the common view was that natural justice, like the right to be heard, applied only when a body acted in a quasi-judicial way. Pure administrative acts were thought to be outside it.
Step 3: Identify the landmark case.
The Indian Supreme Court changed this view in A.K. Kraipak v. Union of India, AIR 1970 SC 150. It held that the line between administrative and quasi-judicial acts had become thin, and fairness must apply to administrative actions too.
Step 4: Connect to the quote.
The observation that natural justice is not confined to the narrow precincts of quasi-judicial functions fits exactly with what the Court said in A.K. Kraipak.
Step 5: Remove the wrong options.
Ridge v. Baldwin, Maradana Mosque Trustees v. Mahmud, and Conway v. Rimmer are important English cases, but this particular Indian principle and wording is tied to A.K. Kraipak.
Step 6: State the answer.
So the principle was laid down in A.K. Kraipak v. Union of India. \[ \boxed{\text{A.K. Kraipak v. Union of India AIR 1970 SC 150}} \]