Because the "Bird's Nest" is different from other buildings, the column structure of "East to West" is very complicated, and the requirements and difficulties for welding technology are very high. Those welders who have been trained and selected are not only completed with high quality and efficiency, as scheduled The task was completed, and his name was engraved on the edge of each weld of the "Bird's Nest". In the words of the management, let countless ordinary welders leave their own tiny traces in this world-renowned Olympic project --- Maybe the public has no chance to see it, but it will never die. What is the most appropriate understanding of this passage? ['Let the builders leave their names is a heartwarming move.', 'For the builder, it is to look up and sign your name.', 'The signature of the builder is responsible for history and for his own life.', 'Ordinary welders leave their marks in the Olympic project.']