The correct answer is option 'B,' which is the 42nd Amendment Act (1976). This amendment expanded the scope of the directive principles under Article 31C of the Indian Constitution.

Explanation:
1. Overview of Directive Principles and Article 31C:
- The Directive Principles of State Policy (DPSP) are a set of guidelines and principles given in Part IV of the Indian Constitution.
- They are non-justiciable in nature, meaning they cannot be enforced by courts. However, they serve as important principles for governance and policy-making.
- Article 31C was inserted into the Constitution by the 25th Amendment Act (1971) to give constitutional protection and precedence to certain directive principles.

2. The 42nd Amendment Act (1976):
- The 42nd Amendment Act is often referred to as the "Mini-Constitution" or the "Constitution of Indira."
- It was introduced during the tenure of Prime Minister Indira Gandhi and brought about significant changes to various aspects of the Constitution.
- This amendment aimed to strengthen the power of the central government and curtail the powers of states.

3. Expansion of Article 31C:
- The 42nd Amendment Act expanded the scope of Article 31C and provided additional protection to certain directive principles.
- Earlier, Article 31C protected only two directive principles: Article 39(b) and Article 39(c). These principles relate to the distribution of resources and the prevention of concentration of wealth and means of production.
- The 42nd Amendment Act added two more directive principles to the protection of Article 31C: Article 39(a) and Article 39(d).
- Article 39(a) directs the state to secure equal justice and free legal aid to economically weaker sections of society.
- Article 39(d) directs the state to secure just and humane conditions of work and maternity relief.
- By including these additional directive principles under Article 31C, the 42nd Amendment Act aimed to prioritize and give precedence to these principles over any laws that may be inconsistent with them.

In conclusion, the 42nd Amendment Act (1976) expanded the scope of the directive principles under Article 31C by adding two more principles, Article 39(a) and Article 39(d), to the protected list. This amendment aimed to prioritize and give constitutional protection to these directive principles.