HELP QUICKLY PLEASE!!In "Run, Kate Shelley, Run," why does the trestle bridge collapse into Honey Creek?

A. A speeding train had jumped off the tracks and crashed into the bridge. B. The bridge had been built long ago by people who did not do a very good job. C. Nearly a week of rain had caused the creek's waters to rise violently and weaken the bridge. D. Lightning struck had struck the bridge, setting it on fire.