How do i find the answer to this question?

Answer is choice D) AC < FH

Think of a door. Imagine tying a string to the handle of the door and to the metal part where the door would touch if the door was closed. The more open the door is, the longer the string would be (if the string is completely taut and there's no slack). This is the hinge theorem in action. The larger the angle, the larger the opposite side. 

Applied to this problem, we have angle G larger than angle B, so the respective opposite sides are larger in this order (FH is larger than AC). This theorem only works if we know the other two sides are fixed in length and are equal. If either AB = GH or BC = FG was false, then the hinge theorem would not work here.