Question

@claire_crites, Happy to help. Let's take a look at (B) and (C). This is a strengthen with a sufficient premise question, so we're looking for the answer choice that, if true, makes the argument valid. If we're able to find out that Selena does possess psychic powers, then it makes sense to say that we've determined whether or not psychic powers are possible. However, what if we find out that her claim is false? Does her claim being false prove that it isn't possible to have psychic powers? Not necessarily, as someone else could have them. Thus, we must make the assumption that Selena is the only individual who could possess psychic powers. This way, if we figure out that she has them or doesn't have them, we will definitely be able to know whether or not it's possible for someone to have psychic powers. (C) says, "It is possible to determine whether Selena has psychic powers." The problem with (C) is that it does not help us to know what happens if Selena does not possess psychic powers. It's still possible that someone else has psychic powers. The conclusion of the stimulus, that we would know whether or not psychic powers are possible even if we discover that Selena doesn't have them, would not be justified with (C), so it's out. (B) says, "If it is possible to have psychic powers, then Selena has them." (B) is great because it ensures the argument's conclusion. (B)'s contrapositive is if Selena doesn't have psychic powers, then it's impossible to have them. This tells us that whether we find that Selena has psychic powers or not, we'll be able to know if it's possible or not possible to have psychic powers. Thus, (B) is correct. Does this make sense? Let us know if you have any more questions!

@Ravi your explanations for B and C are great; can you explain why A is incorrect as well? Thanks!

Hi @Minerva, The problem with A is that it doesn't ensure whether it is possible to have psychic powers or not. It also doesn't connect any general claims to Selena. Hope this helps.

Diagram P-->S Not S ---> Not P Selena having it a the necessary condition how is it that we conclude the sufficient backwards here?