Hi Ellen,
In that one, the first sentence provides that it is wrong to restrict liberty, except perhaps when failing to do so would allow harm. In other words, if it is not wrong to restrict liberty, we know that failing to do so would allow harm:
Wrong to restrict liberty failing to restrict would allow for harm
...the contrapositive of the above statement provides that if failing to restrict something would not allow for harm, it would be wrong to restrict liberty:
failing to restrict would allow for harm Wrong to restrict liberty
Choice (A) works with the statement above for confirmation: if a publication is only offensive, then failing to restrict it would not allow for harm, so it would be wrong to restrict liberty in that scenario:
merely offensive
failing to restrict would allow for harm Wrong to restrict liberty.
Answer choice (C) makes the assertion that restricting liberty is not harmful. This choice is not supported by the stimulus, as the author does not comment on whether government restriction of liberty is harmful or offensive--just that it is
wrong except in limited cases.
I hope that's helpful! Please let me know whether this is clear--thanks!
~Steve