It's a smart-alec question: for stat. (2), if 1 is in S, then 1/1=1 must also be in S. I don't think the question demands these to be two different terms (i.e. that set S will then include 1 AND another 1), but it's left ambiguous, which seems slightly off.
Bottom line, it's down to interpretation of the set: if we are to understand that the set includes at least two terms, 1 and 1/1=1, then stat. (2) is sufficient: if we have 1 and 1, we also have 1+1=2, and if we have 1 and 2, we also have 1+2=3., and the answer is "yes".
But if the mere presence of the single term "1" satisfies the terms of the set from the question stem, since both 1 and 1/1 are equal to 1, then we simply do not know whether or not 3 is also in the set - the statement didn't specify that 1 is the ONLY term in the set, which could also include 3, or 3,000, or -10,000,000 as far as we know.
