Answer: The correct option is
(A) If F and G differ by a constant, then f = g.
Step-by-step explanation: According to the given condition, we have

We are to select the correct statement.
Let F(x) = p(x) and G(x) = p(x) + c, c - constant.
Then, we get

Therefore,

Thus, if F and G differ by a constant, then f = g.
Option (A) is CORRECT.