In the 19th century, there was a significant movement of Indian and Chinese laborers who went to work on various projects around the world. The correct answer to this question is option 'C' which states that they worked in mines, plantations, road and railway construction projects around the world.

Road and Railway Construction Projects:
- Indian and Chinese laborers played a crucial role in the construction of roads and railways in various parts of the world during the 19th century.
- They were employed in projects such as the construction of the Transcontinental Railroad in the United States, the Canadian Pacific Railway, and the British Raj's railway network in India.
- These laborers were known for their hard work and played an instrumental role in the completion of these infrastructure projects.

Mines:
- Indian and Chinese laborers were also recruited to work in mines across the globe.
- They worked in gold and diamond mines in South America, such as those in Brazil and Guyana.
- These laborers were often subjected to harsh working conditions and faced numerous challenges while working in the mines.

Plantations:
- Many Indian and Chinese laborers were taken to work on plantations in different parts of the world.
- They were employed in tea and rubber plantations in countries like Sri Lanka, Malaysia, and Indonesia.
- These laborers were brought in to meet the demand for cheap labor and were often subjected to exploitative working conditions.

Significance:
- The migration of Indian and Chinese laborers during the 19th century was a result of various factors such as economic opportunities, labor shortages, and colonial expansion.
- Their contribution was significant in the development of infrastructure projects, mining industries, and plantations around the world.
- However, it is important to note that these laborers were often treated poorly and faced discrimination and exploitation.

In conclusion, Indian and Chinese laborers in the 19th century played a vital role in various projects globally, including road and railway construction, mining, and plantation work. Their contribution was substantial but often came at the cost of harsh working conditions and mistreatment.