Assuming the order of selection doesn't matter:

Answer:
9c^2
Step-by-step explanation:
The greatest common factor (GCF) is the largest positive integer that divides each of the integers. In this case we have the terms 207c^3 and 108c^2. Both terms can be divided by 9c^2 to get 9c^2(23c + 12). Notice that 23c + 12 can no longer be further simplified so 9c^2 is the GCF.
Subtract 4 from 12 and multiply by 6