What Was the Most Important Lesson Learned by Management in the Wake

What was the most important lesson learned by management in the wake of the 1970 Lordstown riots?

A) the benefits of civil rights legislation
B) the value of having highly educated auto workers
C) not to pay workers too well
D) the need to give workers even better pay and longer vacations to keep them content
E) the need to attend to workers' intrinsic as well as extrinsic motivation