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.