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.
lightning struck had struck the bridge, setting it on fire.

d.
nearly a week of rain had caused the creek's waters to rise violently and weaken the bridge.