Your sig is wrong, I realize you were only intending on multiplying 12 by 0 but in the context of the problem you multiplied the entire thing by 0, thus making 0 the correct answer.
The guy that said bodmas is correct...
You would only multiply the 12 by 0 and then subtract that from the 28... thus equalling 28.
If you put the whole thing in brackets and then multiplied by zero, you would be correct.