Final answer:
The **Indian Ocean trade** network was instrumental in the evolution of the Gupta numeral system, allowing for the exchange of goods and ideas, including advancements in mathematics made during the Gupta Empire.
Step-by-step explanation:
The evolution of the Gupta numeral system was heavily influenced by the Indian Ocean trade network. The Indian Ocean trade route was critical to cultural and commercial exchanges in the region, providing a conduit for the spread of ideas, goods, and scientific knowledge, including mathematical concepts.
The Guptas controlled much of India and their influence extended through trading networks that played a significant role in the development and dissemination of the number systems that they used, particularly the numeral system that included the invention of the number zero.
The Gupta Empire was known for its contributions to the sciences and mathematics, and the flourishing trade across the Indian Ocean under Islam's spread helped to facilitate cultural and scientific exchanges.
Therefore, the advances in Gupta's mathematics, such as the number zero and the concept of pi (π), benefited from and contributed to the thriving mercantile activities along this maritime route.
Therefore, c) Indian Ocean trade is correct answer.