Answer:
First lets simplify the m's. So to simplify we can use this formula
x^n / x^b = x^(n-b)
So that means that 5--7 = 5+7 = 12. So we can cancel out the m at the bottom and get m^12. Seen as we have m^12 on only of one we can take advantage and answer that. But just to prove for the n's we can do same 4--2 = 4+2 = 6. So that also says n^6. So That proved that
c is answer C
