Question: With which band was Guðmundur Gunnarsson's daughter initially the lead singer ?
Sentence (from "Guðmundur Gunnarsson"): The father of the singer Björk (Björk Guðmundsdóttir), he is a nationally known figure in his own right as the leader of the Icelandic Electricians' Union, Rafiðnaðarsamband Íslands (RSÍ).
Relevant evidence: Yes