Find the gcf of the first two terms and the gcf of the last two terms of the polynomial

The answer is C. For the first pair, both 20 and 5 can be evenly divided into 5. There is an h^2 and h^3 but h^2 is correct because the second term cannot be evenly divided into h^3.
For the second pair, 4 and 16 can both be divided into 4. h is only in the third number so it obviously cannot be evenly divided into the last number.