Concept:U. Srinivas is famous for playing the mandolin in Carnatic classical music, adapting a Western instrument to Indian ragas.Explanation:U. Srinivas, born in 1969, was a child prodigy. He began playing mandolin at age six. He was the first to use a five-string electric mandolin for Carnatic music. This allowed him to produce the required gamakas (oscillations). His first public performance was at the Gudur music festival in 1978. He earned the title "Mandolin Srinivas." He received the Padma Shri in 1998 and the Sangeet Natak Akademi Award in 2010. He also collaborated internationally with the fusion band Remember Shakti.Among the given options: Sitar is used in Hindustani music (e.g., Ravi Shankar). Tambura provides a drone, not melody. Nadaswaram is a double-reed wind instrument. Only mandolin matches U. Srinivas's instrument.Answer:Mandolin (Option B)