Step 1: Recall the First Amendment.
The First Constitutional Amendment of 1951 added Articles 31A and 31B and the Ninth Schedule, mainly to protect land reform laws.
Step 2: Identify the dispute.
People asked whether Parliament could amend fundamental rights at all.
Step 3: Find the case.
This question came up in Shankari Prasad Singh Deo v. Union of India (1951), the first big amendment case.
Step 4: Recall the ruling.
The Supreme Court held that an amendment under Article 368 is not a law under Article 13, so Parliament could amend fundamental rights. The amendment was upheld.
Step 5: Rule out the others.
Indra Sawhney is about reservations, MC Mehta about environment, and Nanavati a famous murder trial. None challenged the First Amendment.
Answer: Shankari Prasad Singh Deo v. Union of India (Option 4).