Step 1: Understanding the Question:
The question asks us to identify the specific judicial decision that struck down Article 124A (which was introduced to establish the National Judicial Appointments Commission) as unconstitutional.
Step 2: Key Concepts and Approach:
Parliament enacted the 99th Constitutional Amendment Act, 2014, inserting Articles 124A, 124B, and 124C to replace the Collegium system with the National Judicial Appointments Commission (NJAC).
We must identify the ruling that evaluated this amendment against the Basic Structure doctrine.
Step 3: Detailed Explanation:
• The 99th Amendment & NJAC: The amendment sought to create a 6-member commission (comprising the CJI, senior judges, the Law Minister, and eminent persons) to appoint Supreme Court and High Court judges.
• Supreme Court Advocates-on-Record Association v. Union of India (2015): Commonly known as the "Fourth Judges Case," a 5-judge constitution bench evaluated the amendment.
• Independence of the Judiciary: By a 4:1 majority, the Court struck down the 99th Amendment and Article 124A as unconstitutional.
• The Core Reason: The Court held that the independence of the judiciary is a basic feature of the Constitution. The inclusion of the executive (Law Minister) in the selection process compromised this independence.
• Revival of the Collegium: Consequently, the Collegium system was revived.
Step 4: Final Answer:
The judgment that declared Article 124A unconstitutional is Supreme Court Advocates on Record Association and Another v. Union of India (2015). Hence, Option B is correct.