Explanation:

- The Indian Constitution includes several directives aimed at promoting the welfare of workers and participatory management.

- Option 1: Article 39A of the Constitution of India - Relates to promoting justice and free legal aid.

- Option 2: Article 43A of the Constitution of India - Correct. This article specifically provides for workers' participation in the management of industries, encouraging a collaborative approach.

- Option 3: Article 42 of the Constitution of India - Pertains to provision for just and humane conditions of work and maternity relief.

- Option 4: Article 43B of the Constitution of India - Encourages the promotion of cooperatives, not workers' participation in management.