Final answer:
The fabric that changed the world, which was first domesticated in the Indus Valley 5,000 years ago, is cotton. Cotton has played a significant role in the history of textiles, particularly in India, which was a formidable presence in the global textile trade. The correct answer is option A.
Step-by-step explanation:
In Old Delhi, the Chandel Chowk Bazaar has long been a central hub for traders. The fabric that is mentioned as having been domesticated in the Indus Valley 5,000 years ago and which changed the world is cotton. Cotton has been cultivated since around 4500 BCE and was the standard for clothing during the Middle Ages. Furthermore, Indian textiles, including cotton, were greatly desired for their quality and durability. These goods were a significant part of India's economy, and they played a crucial role in the international trade, particularly as part of the mercantile system that dominated global economics of the past.
Historically, cotton was handwoven on wooden looms, which was a labor-intensive process. This process changed with the onset of the Industrial Revolution and the invention of textile machinery, which greatly reduced the manual labor needed to produce cotton textiles.
Given the importance of cotton in the textile history, particularly in the context of India, it is clear that cotton is the correct answer (A).