Explanation:

- Indian Labour Conference: It is a tripartite body involving representatives of government, employers, and workers.

- Standing Labour Committee: Also tripartite in nature, it prepares the agenda for the Indian Labour Conference and includes the three parties.

- International Labour Organisation: This is an international tripartite body, with representation from governments, employers, and workers.

- Wage board: Usually consists of representatives from employers and employees, but not always from the government, so it cannot always be called tripartite machinery.

Correct Answer: Option 4 - Wage board