what does EC mean, im trying to turn in my extra credit for my high school online classes(i dont know if its like only a high school thing or not) and next to the assignment name it says "EC DO NOT TURN ANYTHING IN" ??

Doug plans to end his adventure story by introducing a new character during the climax. the new character happens to be an experienced guide who will lead the protagonist down a treacherous mountain and into safety. explain the problem with his plan.