Hi!
That's absolutely right. Answer choice (A) is really just the reversal of answer choice (C). But just to break it down a bit further...
The stimulus can be distilled down to essentially:
Premise: Increased taxation is necessary to solve homelessness
Conclusion: We should increase taxation
Since our job is to support this argument, one way to do that would be to essentially say: Premise
Conclusion. In other words,
if increased taxation is necessary to solve homelessness
then we should increase taxation. That's exactly what answer choice (C) does here.
Answer choice (A), on the other hand, basically gives us a rule that says: Conclusion
Premise. But, since the conclusion is not a given here, this rule doesn't really help the argument.
Hope that helps!