Explanation:

- Industrial Tribunal: These tribunals are set up by the government to adjudicate on industrial disputes. They handle issues like wages, work conditions, and employment terms.

- National Tribunal: This tribunal deals with industrial disputes that have a national importance or could affect multiple states. It provides a platform for resolving issues that may influence large sections of the industry.

- Labour Court: Labour courts focus on individual or specific grievances between employers and workers. They handle issues such as wrongful termination and other labor rights violations.

- Correct Answer: Option 4 - all of the above. Each plays a different but integral role in the settlement of industrial disputes.