It looks like youre talking about 25 and 26 in the practice questions.
For 25, the author is rejecting the claim that we should not eat conscious creatures on the grounds that there is a possibility under which the eating of conscious creatures would not be morally impermissible. This claim (which is what we are examining) undermines the idea that anuimal's conciousness is enough of a reason not to eat them.
For 26, I'm unclear on your question, but it looks like you are referring to why D is right and D is wrong. The author cites statistics that show no clear connection between the number of police officers and crime rates in order to argue against the idea that hiring more cops is needed to reduce crime.
These stats do not prove that there is no relationship, but rather that it shows that it is not the case that hiring more police is necessary to reduce crime. The type of statistics that the author cites are not enough to prove the lack of a relationship, but they are able to prove that police hiring is not the only factor in crime rates.