As a Result of Her Research into the Causes of the Challenger

As a result of her research into the causes of the Challenger disaster in 1986, sociologist Diane Vaughn discovered

A) a small group of engineers who sabotaged the fuel tank of the space shuttle.
B) executives who illegally hired a foreign contractor to supply parts at a cheaper price.
C) politicians that pressured NASA to launch before the space shuttle was ready to fly.
D) that NASA had a culture that had come to accept flaws as normal and acceptable.
E) All of the above