请教一道feifei逻辑题

104. That the policy of nuclear deterrence has worked thus far is unquestionable. Since the end of the Second World War, the very fact that there were nuclear armaments in existence has kept major powers from using nuclear weapons, for fear of starting a worldwide nuclear exchange that would make the land of the power initiating it uninhabitable. The proof is that a third world war between superpowers has not happened.
Which one of the following, if true, indicates a flaw in the argument?
A.Maintaining a high level of nuclear armaments represents a significant drain on a country’s economy.

B.From what has happened in the past, it is impossible to infer with certainty what will happen in the future, so an accident could still trigger a third world
  war between superpowers.

C.Continuing to produce nuclear weapons beyond the minimum needed for deterrence increase the likelihood of a nuclear accident.

D.The major powers have engaged in many smaller-scale military operations since the end of the Second World War, while refraining from a nuclear
confrontation.

E.It cannot be known whether it was nuclear deterrence that worked, or some other factor, such as a recognition of the economic value of remaining at

答案是选E，可是B错在那里呢？？~~~
  peace.