I summed all the numbers in each row, which gives 35, 31, 29, 28, 38

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.

(Deleted.)

Though list B contains 4-3, so either B or D would be valid as ordering does not matter

When I first solved it I selected B but when I sat down to type it down I spotted 3-4 and thought that was the one I had gone with originally.

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 :(