Question: Peter Sinfield was part of what rock group with fellow member Robert Fripp?
Sentence (from "King Crimson"): The band has undergone numerous formations throughout its history of which 21 musicians have been members; since January 2017 it has consisted of Robert Fripp, Jakko Jakszyk, Tony Levin, Mel Collins, Pat Mastelotto, Gavin Harrison, Bill Rieflin and Jeremy Stacey.
Relevant evidence: Yes