That crossed my mind too, but since they said "I have three 2D arrays", I assumed that these are 3x3 arrays instead of pseudo 1D arrays but I admit there is ambiguity. Contributing to the fuzziness was the fact that all rows had three digits. 😉
Fortunately, both solutions work equally well, even if there is only one column in the inputs, or even if the number of columns differ for the three 2D array inputs. 🙂