A. f
Step-by-step explanation:
The given expression is
![(7f^{2}-12f)7f^{2}-12f](/tpl/images/0466/6934/cb826.png)
As you can observe in the given expression, a common factor to all terms is
, because it's present in each term.
To a factor be common, it has to be present in all terms, like
in this case.
has
as a factor.
has
as a factor.
Therefore, the right answer is A.