Geography · Indian Drainage System

With reference to the drainage network of the Ganga basin, consider the following statements: I. The Yamuna, regarded as one of the most significant tributaries of the Ganga, meets it at Prayagraj after flowing along the right bank of the Ganga for most of its course. II. Rivers such as the Chambal and Betwa become part of the Ganga basin indirectly, as they first merge with the Yamuna before the latter joins the Ganga. III. The Son River, which rises in the Amarkantak highlands, joins the Ganga as one of its important right-bank tributaries. How many of the statements given above are correct?