The answer is D because the whole point of a metaphor is to compare things in a unique way and it makes people really think.
I hope this helped :)
To refute the claims of proponents of slavery.
This should be a slippery slope logical fallacy.
That's when you start with a thing and swiftly move on to the consequences that may come from that thing and are usually negative. Here you have the slippery slope that if you don't do your homework, you are bound to fail and end up being a failure while it is not so in reality.