Answer: D. Out-of-control consumerism.
Explanation: Zombies are a perfect symbol for most things that we humans do in an "auto-pilot" way, i.e., as a result of our conditioning, without ever reflecting or questioning the necessity of those things, and blind to their consequences. Whether a victim lives or dies is not part of a zombie's mind; it just wants to eat brains whatever the consequences, and the same is true for us humans and the consequences of our endless consumerism.
