Concept:The correct word must contrast with "drawn back in fear", which means the same as "recoil".Explanation:"Recoil" means to suddenly move back or shrink away, often because of fear.The boys used to "draw back" from the bully, so they used to recoil.The word "but" shows a change from their past behaviour.Therefore, "this time they did not recoil" fits the meaning perfectly.The other options — "advance", "agree", and "retaliate" — do not match the idea of drawing back.Answer:D. recoil