For 24 the factors are 1, 2, 3, 4, 6, 8, 12, and 24. For 36 the factors are 1, 2, 3, 4, 6, 9, 12, 18, and 36. For 27 the factors are 1, 3, 9, and 27. And lastly, 7 is a prime number so it's just 1, and 7.
Factor out the 3 in the numerator and apply the difference of squares, factor out the 6 in the denominator, and reduce where applicable. It'll all cone out to look like option C.