E's problem is that, based on E, we still need another assumption to make the argument stand: that people 18-25 have the tendency to continue to work if they get minor hurts.
I go for A. B/C/D can be ruled out. E actually is irrelevant. The best answer be able to provide another reason to explain the fact alleged in the argument. E is not that strong to explain, because :
1)there is no comparison between 18-25 and 26 up
2)frequently changing jobs doesn't necessarily end up safer jobs.