Question: Pentatonix, the five-member American a cappella group lost their vocalist Avi Kaplan in 2017 at the same time as their tribute to which group received over 250 million views?
Sentence (from "Pentatonix"): When Sony's Epic Records dropped the group after "The Sing-Off", the group formed its YouTube channel, distributing its music through Madison Gate Records, a label owned by Sony Pictures.
Relevant evidence: No