I'm sorry to say it, but you aren't correct. The answer was definately X. You will not find anyone who agrees with you here.
EDIT: Field for a single bar magnet
check out the link, You'll see that the magnetic field on one pole doesn't turn around on itself within the width of the magnet
The sodium carbonate solution ( basic salt solution) will supply carbonate ions which will neutralise the acid, releasing heat. I'm about 90% sure thats why, I dont think it woudl have anything to do with other products of their creation.