Option b is the correct answer. "Sarthwah" refers to a convoy or group of merchants who would travel together for mutual protection and assistance during their journeys. These merchants would collectively undertake trade expeditions, often in caravans, to ensure safety from bandits, harsh conditions, and other risks that came with long-distance travel. The Sarthwah played an important role in the economic development of ancient India. They helped to promote trade and commerce and to spread culture and information throughout the country.