The foil method is a method to factor an expression. For example: FFWw. The question is simply trying to confuse you. Turn FFWw into (FF)(Ww) then solve as shown:
I think its c because a pivot joint would be circular movement in only one manner and that matches the turning of a door knob. a hinge joint does not swivel like a chair or move like a shower head, and a cabinet door, in my opinion would be like a hinge joint
