Explanation:
the first option : -(m¹²n⁶)/2
why ?
we can go through factor by factor of the multiplication/fraction.
2/-4 = -1/2
m⁹/m^-3 = m^(9 - -3) = m¹²
n⁴/n^‐2 = n^(4 ‐ -2) = n⁶
when we put all 3 factors back together, we get the mentioned result.