Option (C) The Ganga is correct. The textbook context explicitly states that the Ganga 'river system is the largest in India having a number of perennial and non-perennial rivers originating in the Himalayas in the north and the Peninsula in the south, respectively.' While the Indus is mentioned as 'one of the largest river basins of the world' with a total area of 11,65,000 sq. km, its catchment area within India is only 321,289 sq. km. The Ganga basin, however, is the largest river basin entirely within India. The Brahmaputra and Krishna are both listed among the 14 major river basins but are not described as the largest.