Step 1: Understanding the term 'Green Gold'.
The term 'Green Gold' is used to describe a plant that has high economic value, is renewable, and has a wide range of uses.
Step 2: Analysis of options.
- Silk: Known as the 'Queen of Textiles,' but not referred to as 'Green Gold.'
- Bamboo: Correct. It grows rapidly, is eco-friendly, and is used in construction, furniture, paper, textiles, and handicrafts. Its economic and ecological importance gives it the title 'Green Gold.'
- Coir: Refers to fibre from coconut husk, used in mats and ropes, but not called 'Green Gold.'
- Cotton: Called 'White Gold' in India due to its agricultural and economic importance, not 'Green Gold.'
Step 3: Conclusion.
Therefore, Bamboo is popularly called 'Green Gold.'