The correct option is B Krishna
1:Nagarjuna Sagar Dam is a masonry dam across the Krishna river at Nagarjuna Sagar which straddles the border between Guntur district, Andhra Pradesh and Nalgonda district, Telangana
2:It is an undertaking of the Government of Andhra Pradesh for utilizing the water of the Krishna river. It was inaugurated on Aug. 4, 1967. It is situated near Nandikonda Village in Miryalgude Taluk of Nalgonda district. The Nagarjun Sagar Project comprises the construction of a 1450 metre long and 92 metre high dam. The dam has been completed. The project will ultimately irrigate about 8•95 lakh hectares.