Question: What type of instrument is the Sagar Veena, invented by the father of musician Noor Zehra?
Sentence (from "Gottuvadhyam"): The chitravina (also known as chitra veena, chitraveena, chitra vina, hanumad vina, or mahanataka vina) is a 20 or 21-string fretless lute in Carnatic music.
Relevant evidence: Yes