Question: Which of the following is best known as the main volcalist of the South Korean group GFriend: Seth Putnam or Yuju?

Context paragraphs:
Kim Ye-won: Kim Ye-Won (born August 19, 1998), widely known by her stage name Umji, is a south korean singer.  She is best known as the Lead Rapper, Vocalist and Maknae of the girl group GFriend.

Yuju (singer): Choi Yu-na (born October 4, 1997), better known by her stage name Yuju, is a South Korean singer.  She is best known as the main vocalist of the South Korean girl group GFriend.

The Awakening (EP): The Awakening is the fourth extended play (EP) by South Korean girl group GFriend.  The EP was released digitally and physically by Source Music on March 6, 2017 and distributed by LOEN Entertainment.  The album consists of six songs, including the single "Fingertip".

Seth Putnam: Seth Edward Putnam (May 15, 1968 – June 11, 2011) was an American musician who was the founder of grindcore band Anal Cunt.  He was known for his brutal screaming and lyrics that either shock, offend, or invoke morbid humor.  Throughout his career, Putnam had been involved in many side projects, including backing vocals on Pantera's "The Great Southern Trendkill."

Flower Bud (EP): Flower Bud is the second extended play (EP) by South Korean girl group GFriend.  It was released by Source Music on July 23, 2015 and distributed by KT Music.  The album contains four songs, including the single "Me Gustas Tu", and one instrumental track.  The album debuted at number six on the Gaon Album Chart and has sold more than 18,000 units.  Musically, the album is in the bubblegum pop genre and is similar in style to Korean girl groups of the 1990s.  Most of the tracks on the album were written by Iggy and Seo Yong-bae, who worked with the group on their debut album, "Season of Glass".

Snowflake (EP): Snowflake is the third extended play (EP) by South Korean girl group GFriend.  It was released by Source Music on January 25, 2016 and distributed by LOEN Entertainment.  The album contains five songs, including the single "Rough", and two instrumental tracks.  The album debuted at number two on the Gaon Album Chart and has sold more than 33,000 units.  GFriend promoted the album with a series of televised live performances on South Korea's music shows, winning a total of 15 music show awards.  "Rough" was also commercially successful, topping the Gaon Digital Chart and selling more than one million digital downloads.  Musically, the album is similar in style to K-pop from the late 1990s and 2000s.

Eunha (singer): Jung Eun-bi (born May 30, 1997), widely known by her stage name Eunha, is a South Korean singer and actress.  She is best known as the lead vocalist of the girl group GFriend.

GFriend discography: The following is the discography of the six-member South Korean girl group GFriend.  The group has released one full-length album and five extended plays.

Season of Glass (EP): Season of Glass is the debut extended play (EP) by South Korean girl group GFriend.  It was released by Source Music on January 15, 2015 and distributed by KT Music.  The album contains three songs, including the single "Glass Bead", and two instrumental tracks.  The album peaked at number nine on the Gaon Album Chart and has sold more than 10,000 units.  GFriend promoted the album with a series of televised live performances on South Korea's music shows.  Their debut was often compared to Girls' Generation's debut, with the music and choreography of "Glass Bead" being reminiscent of "Into the New World".

GFriend: GFriend (Hangul: 여자친구 ; RR: "Yeoja Chingu " ) is a six-member South Korean girl group formed by Source Music in 2015.  The group consists of Sowon, Yerin, Eunha, Yuju, SinB, and Umji.  They made their debut with the EP "Season of Glass" on January 16, 2015.  GFriend won several 2015 female rookie awards and has garnered momentum since their debut, despite coming from a small company.  In 2016, they continued their success with their third EP "Snowflake" and won first place on many music shows with the title song "Rough".  They released their first full-length album "LOL" in July 2016.

Supporting paragraphs: Seth Putnam Yuju (singer)
Answer: Yuju