Question: On which channel did a television series air in 2015 that starred the main vocalist of the South Korean girl group Apink?

Related documents: [0]  [DOC] Cheer Up! (; lit. " Sassy, Go Go") is a 2015 South Korean television series starring Jung Eun-ji, Lee Won-keun, Cha Hak-yeon, Ji Soo and Chae Soo-bin. It aired from October 5, 2015 until November 10, 2015 on KBS2 every Monday and Tuesday at 22:00 KST for 12 episodes. [END] 
[1]  [DOC] Jung Eun-ji (born Jung Hye-rim, on August 18, 1993), better known by the mononym Eunji, is a South Korean singer, songwriter, actress and voice actress. She is best known as the main vocalist of the South Korean girl group Apink. Jung made her acting debut in the coming-of-age drama, "Reply 1997" in 2012. She has since had roles in "That Winter, the Wind Blows" (2013), "Trot Lovers" (2014) "Cheer Up!" (2015), in addition to various voice acting roles. She released her debut solo album, "Dream", in 2016. [END]  
Answer: KBS2
KBS2