Avriel Benjamin "Avi" Kaplan won what show as part of the group Pentatonix?
Pentatonix:  Pentatonix formed in 2011 and subsequently won the third season of NBC's "The Sing-Off," receiving $200,000 and a recording contract with Sony Music. Avi Kaplan: Avriel Benjamin "Avi" Kaplan is an American singer and songwriter, most well known as a past member of the a cappella group Pentatonix.
i don't know