Option a is the correct answer The credit for making the capital city of the Vijayanagara Empire one of the biggest cities in the 15th century goes to Deva Raya I. He realized that the scarcity of water supply, both for drinking and for irrigation, was restricting the growth of the royal capital. In around 1410 he had a barrage constructed across the Tungabhadra River and commissioned a 24 km long aqueduct from the Tungabhadra River to the capital.