challenge: Who are the main actors in the South Korean television series 'Manhole'?
  
  A. Kim Jae-joong, Uee, Cha Sun-woo, Jung Hye-sung
  B. Lee Min-ho, Song Hye-kyo, Park Bo-gum, Jun Ji-hyun
  C. Lee Jong-suk, Suzy, Nam Joo-hyuk, Han Hyo-joo
  D. Park Seo-joon, Park Min-young, Ji Chang-wook, Kim So-hyun
  Answer: 