challenge: What is the significance of the site called Llech Gwen in Gwen Ystrat according to the poem about Urien's victory?
  
  A. It was the location where the invaders launched their attack
  B. It was where the fighting took place since dawn at the entrance to a ford
  C. It was the site where Urien and the invaders negotiated a truce
  D. It was the place where Urien's warband camped before the battle
  Answer: 