Answer:
to explain how one event or action leads to another
The key sentence is: "<span>We are apt to shut our eyes against a painful truth, and listen to the song of that siren till she transforms us into beasts." This means that if the leaders continue to act like nothing is wrong, they will gradually become desensitized to their wrongdoings until they think their actions are right. no matter what.
The line "</span><span>I consider it as nothing less than a question of freedom or slavery" may appear to be similar, but that is not talking about the issue itself yet, but just about the magnitude of it, or how serious the issue is that it needs an open discussion.</span>
A parallel sentence mentions the same grammatical expression twice. I would go with "D". 'Passed' and 'Demonstrated' are both past tense words that express the same past tense grammatical idea.
If you have more questions, feel free to ask me.
I think that the answer for "site" should be c. location.
