The GCF of 14abc and 28a^2 b^2 c^3 would be the second option, 14abc.
How? We need to find the "Greatest Common Factor".
So between 14 & 28 is 14, and between a and a^2 is A, between b and b^2 is B, and c between c^3 is C, obviously.
That would leave us with 14abc, which we would consider the greatest common factor.
The correct option among the other answer choices is as follows: B.