The correct option is B Fresh in upper reaches and salty in the lower reaches
The luni river originates from the Naga hills of the Aravali range in Ajmer district of Rajasthan from a height of 772 meters. Here it is known as sagarmati. This river has fresh water during the first hundred kilometers but as it reaches to Balotra in Barmer, the water starts to turn saline from the rich salt content in the soil. After that it is known as Luni. This river ends in the marshy lands of the Rann of Kutch.