Which amongst the following is the longest River?

The length of a river is its total course measured in kilometres from source to mouth, based on figures published by national water-resource authorities; among a given set of rivers, the one with the greatest such length is the longest.

Godavari's length exceeds every other river in this set, including its closest competitor Krishna, by a clear margin confirmed by Central Water Commission data, so it is unambiguously the longest river among the four. It is also known as the 'Dakshin Ganga' (Ganga of the South) for its size and cultural importance in Peninsular India.