Answer:
C
Explanation:
We don't need to know which pole is in the bars. We just need to see that the lines of the magnetic field, represented by the iron filings, are leaving one bar and joining another - we don't need to know which bar is. To do that, we should define what is the North Pole, where the lines leave, and what is the South Pole, where the lines go.
If we had equal poles, the lines would be pointing out the bars like that <<<< BAR >>>>>
<<<<<BAR>>>>>
not joining one or another.
