The correct response is “C. Germany’s attack on Russia was
similar to betraying all the rules of civilization.”
When Joseph Stalin addressed his people during this radio
broadcast, it was to communicate that Germany had attacked Russia despite a
non-aggression act (or peace treaty).
Thus, Stalin was mentioning how Russia was betrayed by Germany. Additionally, because cannibalism is generally
seen to be innately wrong by civilized societies, Stalin alludes to how waging
war when peace was communicated as the goal is low/uncivilized and even
cannibal-like.