Question

While the threat of mutually assured destruction seemed to fade with the end of the Cold War, the threat of _____ still exists.

Answer 1

I don't think that right now there is a threat of the spread of Communism or of proxy wars,(options A and D are false) but the problem which is still present is the problem of proliferation of the weapons of mass distraction: especially, as they are getting cheaper and easier to produce. 
(answer B).

Also, countries no longer have colonies in the strict sense, so also option C is false