An interesting brain teaser
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Then for the answers 34, 35, 35, 38 for which 34 is the only result we didn’t see yet. Therefore I think it’s A.
But in the solution they motivate the specific selection of B by stating that in the provided lists of pairs, the pairings are all with the greater number first.
Hence actually what I typed above is incorrect and the correct answer is B.
Sorry about that :(